chore: prepare releases/v4.15.0 branch

Author: kim-em

RELEASES.md

@@ -11,7 +11,7 @@ of each version.
 v4.15.0
 ----------
 
-Development in progress.
+Release candidate, release notes will be copied from the branch `releases/v4.15.0` once completed.
 
 v4.14.0
 ----------
@@ -88,7 +88,7 @@ v4.13.0
   * [#4768](https://github.com/leanprover/lean4/pull/4768) fixes a parse error when `..` appears with a `.` on the next line
 
 * Metaprogramming
-  * [#3090](https://github.com/leanprover/lean4/pull/3090) handles level parameters in `Meta.evalExpr` (@eric-wieser)  
+  * [#3090](https://github.com/leanprover/lean4/pull/3090) handles level parameters in `Meta.evalExpr` (@eric-wieser)
   * [#5401](https://github.com/leanprover/lean4/pull/5401) instance for `Inhabited (TacticM α)` (@alexkeizer)
   * [#5412](https://github.com/leanprover/lean4/pull/5412) expose Kernel.check for debugging purposes
   * [#5556](https://github.com/leanprover/lean4/pull/5556) improves the "invalid projection" type inference error in `inferType`.

src/CMakeLists.txt

@@ -12,7 +12,7 @@ project(LEAN CXX C)
 set(LEAN_VERSION_MAJOR 4)
 set(LEAN_VERSION_MINOR 15)
 set(LEAN_VERSION_PATCH 0)
-set(LEAN_VERSION_IS_RELEASE 0)  # This number is 1 in the release revision, and 0 otherwise.
+set(LEAN_VERSION_IS_RELEASE 1)  # This number is 1 in the release revision, and 0 otherwise.
 set(LEAN_SPECIAL_VERSION_DESC "" CACHE STRING "Additional version description like 'nightly-2018-03-11'")
 set(LEAN_VERSION_STRING "${LEAN_VERSION_MAJOR}.${LEAN_VERSION_MINOR}.${LEAN_VERSION_PATCH}")
 if (LEAN_SPECIAL_VERSION_DESC)