Upgrade lspconfig to be compatible with nvim 0.11+

Previous calls to
```
require('lspconfig')[server_name].setup(server)
```

...are deprecated now that we're in nvim 0.11, and not going to work in
nvim 0.12.

This commit comes from a (currently-open) PR to kickstart.nvim:
nvim-lua#1590

The hack to emmet-language-server is reverted, and in the next commit, I
will attempt to get the emmet-language-server working again for Elixir
files.

Author: TheDDMbassy

lua/plugins/lsp.lua

@@ -221,48 +221,92 @@ return { -- LSP Plugins
       --  By default, Neovim doesn't support everything that is in the LSP specification.
       --  When you add blink.cmp, luasnip, etc. Neovim now has *more* capabilities.
       --  So, we create new capabilities with blink.cmp, and then broadcast that to the servers.
-      local capabilities = require('blink.cmp').get_lsp_capabilities()
-
-      -- Enable the following language servers
-      --  Feel free to add/remove any LSPs that you want here. They will automatically be installed.
+      -- NOTE: The following line is now commented as blink.cmp extends capabilites by default from its internal code: 1Code has comments. Press enter to view.
+      -- https://github.com/Saghen/blink.cmp/blob/102db2f5996a46818661845cf283484870b60450/plugin/blink-cmp.lua
+      -- It has been left here as a comment for educational purposes (as the predecessor completion plugin required this explicit step).
       --
-      --  Add any additional override configuration in the following tables. Available keys are:
-      --  - cmd (table): Override the default command used to start the server
-      --  - filetypes (table): Override the default list of associated filetypes for the server
-      --  - capabilities (table): Override fields in capabilities. Can be used to disable certain LSP features.
-      --  - settings (table): Override the default settings passed when initializing the server.
-      --        For example, to see the options for `lua_ls`, you could go to: https://luals.github.io/wiki/settings/
+      -- local capabilities = require("blink.cmp").get_lsp_capabilities()
+
+      -- Language servers can broadly be installed in the following ways:
+      --  1) via the mason package manager; or
+      --  2) via your system's package manager; or
+      --  3) via a release binary from a language server's repo that's accessible somewhere on your system.
+
+      -- The servers table comprises the following sub-tables:
+      -- 1. mason
+      -- 2. others
+      -- Both these tables have an identical structure of language server names as keys and
+      -- a table of language server configuration as values.
+      ---@class LspServersConfig
+      ---@field mason table<string, vim.lsp.Config>
+      ---@field others table<string, vim.lsp.Config>
       local servers = {
-        emmet_language_server = {},
-        ruby_lsp = {},
-        -- clangd = {},
-        -- gopls = {},
-        -- pyright = {},
-        -- rust_analyzer = {},
-        -- ... etc. See `:help lspconfig-all` for a list of all the pre-configured LSPs
-        --
-        -- Some languages (like typescript) have entire language plugins that can be useful:
-        --    https://github.com/pmizio/typescript-tools.nvim
-        --
-        -- But for many setups, the LSP (`ts_ls`) will work just fine
-        ts_ls = {},
+        --  Add any additional override configuration in any of the following tables. Available keys are:
+        --  - cmd (table): Override the default command used to start the server
+        --  - filetypes (table): Override the default list of associated filetypes for the server
+        --  - capabilities (table): Override fields in capabilities. Can be used to disable certain LSP features.
+        --  - settings (table): Override the default settings passed when initializing the server.
+        --        For example, to see the options for `lua_ls`, you could go to: https://luals.github.io/wiki/settings/
         --
+        --  Feel free to add/remove any LSPs here that you want to install via Mason. They will automatically be installed and setup.
+        mason = {
+          -- emmet_language_server = {
+          --   filetypes = {
+          --     'css',
+          --     'eelixir',
+          --     'elixir',
+          --     'heex',
+          --     'html',
+          --     'javascript',
+          --     'javascriptreact',
+          --     'less',
+          --     'sass',
+          --     'scss',
+          --     'typescriptreact',
+          --   },
+          --   -- init_options = {
+          --   --   includeLanguages = {
+          --   --     eelixir = 'html',
+          --   --     elixir = 'html',
+          --   --     heex = 'html',
+          --   --   },
+          --   -- },
+          -- },
+          ruby_lsp = {},
+          -- clangd = {},
+          -- gopls = {},
+          -- pyright = {},
+          -- rust_analyzer = {},
+          -- ... etc. See `:help lspconfig-all` for a list of all the pre-configured LSPs
+          --
+          -- Some languages (like typescript) have entire language plugins that can be useful:
+          --    https://github.com/pmizio/typescript-tools.nvim
+          --
+          -- But for many setups, the LSP (`ts_ls`) will work just fine
+          ts_ls = {},
+          --
 
-        lua_ls = {
-          -- cmd = { ... },
-          -- filetypes = { ... },
-          -- capabilities = {},
-          settings = {
-            Lua = {
-              completion = {
-                callSnippet = 'Replace',
+          lua_ls = {
+            -- cmd = { ... },
+            -- filetypes = { ... },
+            -- capabilities = {},
+            settings = {
+              Lua = {
+                completion = {
+                  callSnippet = 'Replace',
+                },
+                -- You can toggle below to ignore Lua_LS's noisy `missing-fields` warnings
+                -- diagnostics = { disable = { 'missing-fields' } },
+                diagnostics = { globals = { 'vim', 'require' } },
               },
-              -- You can toggle below to ignore Lua_LS's noisy `missing-fields` warnings
-              -- diagnostics = { disable = { 'missing-fields' } },
-              diagnostics = { globals = { 'vim', 'require' } },
             },
           },
         },
+        -- This table contains config for all language servers that are *not* installed via Mason.
+        -- Structure is identical to the mason table from above.
+        others = {
+          -- dartls = {},
+        },
       }
 
       -- Ensure the servers and tools above are installed
@@ -278,58 +322,32 @@ return { -- LSP Plugins
       --
       -- You can add other tools here that you want Mason to install
       -- for you, so that they are available from within Neovim.
-      local ensure_installed = vim.tbl_keys(servers or {})
+      local ensure_installed = vim.tbl_keys(servers.mason or {})
       vim.list_extend(ensure_installed, {
         'stylua', -- Used to format Lua code
         -- 'vale',
       })
       require('mason-tool-installer').setup { ensure_installed = ensure_installed }
 
+      -- Either merge all additional server configs from the `servers.mason` and `servers.others` tables
+      -- to the default language server configs as provided by nvim-lspconfig, or
+      -- define a custom server config that's unavailable on nvim-lspconfig.
+      for server, config in pairs(vim.tbl_extend('keep', servers.mason, servers.others)) do
+        if not vim.tbl_isempty(config) then
+          vim.lsp.config(server, config)
+        end
+      end
+
+      -- After configuring our language servers, we now enable them.
       require('mason-lspconfig').setup {
         ensure_installed = {}, -- explicitly set to an empty table (Kickstart populates installs via mason-tool-installer)
-        automatic_enable = {
-          exclude = {
-            -- HACK: I was unable to get the `filetypes` and `init_options` working in the emmet table above, and this
-            -- was the solution :(
-            'emmet_language_server',
-          },
-        },
-        automatic_installation = false,
-        handlers = {
-          function(server_name)
-            local server = servers[server_name] or {}
-            -- This handles overriding only values explicitly passed
-            -- by the server configuration above. Useful when disabling
-            -- certain features of an LSP (for example, turning off formatting for ts_ls)
-            server.capabilities = vim.tbl_deep_extend('force', {}, capabilities, server.capabilities or {})
-            require('lspconfig')[server_name].setup(server)
-          end,
-        },
+        automatic_installation = true, -- automatically run vim.lsp.enable() for all servers that are installed via Mason
       }
 
-      -- HACK: See above hack
-      require('lspconfig')['emmet_language_server'].setup {
-        filetypes = {
-          'css',
-          'eelixir',
-          'elixir',
-          'heex',
-          'html',
-          'javascript',
-          'javascriptreact',
-          'less',
-          'sass',
-          'scss',
-          'typescriptreact',
-        },
-        init_options = {
-          includeLanguages = {
-            eelixir = 'html',
-            elixir = 'html',
-            heex = 'html',
-          },
-        },
-      }
+      -- Manually run vim.lsp.enable for all langauge servers that are *not* installed via Mason
+      if not vim.tbl_isempty(servers.others) then
+        vim.lsp.enable(vim.tbl_keys(servers.others))
+      end
     end,
   },
   {