Update release notes

Author: avh4

CHANGELOG.md

@@ -5,6 +5,7 @@ New features:
 
 Bug fixes:
   - `module exposing` listings containing comments no longer add extra leading spaces
+  - Redundant import aliases (when the alias is the same as the module name) are now removed
 
 Other changes:
   - Native binaries are now provided for MacOS ARM64 (previous version required Rosetta)

Release Notes/0.8.6.md

@@ -1,10 +1,14 @@
 ## Much, much faster; Many, many contributors
 
+Thanks to the contributions of many (see below), elm-format is now much faster.
+(Testers of the pre-release saw an 11x speedup on MacOS ARM, and a 4x speedup on other platforms.)
+
 New features:
   - File are now processed in parallel
 
 Bug fixes:
   - `module exposing` listings containing comments no longer add extra leading spaces
+  - Redundant import aliases (when the alias is the same as the module name) are now removed
 
 Other changes:
   - Native binaries are now provided for MacOS ARM64 (previous version required Rosetta)
@@ -31,4 +35,5 @@ or [download from the release page](https://github.com/avh4/elm-format/releases/
   - @tfausak for linux-aarch64 build script updates
   - @supermario for mac-arm64 build script updates
   - [Lamdera](https://www.lamdera.com/) for providing CI runners to build the MacOS ARM64 release binaries
-  - Elm community members for testing the new binaries
+  - Elm community members for testing the new binaries and npm packages
+  - ... and anyone who's contributed to cross-compilation support in ghc or nix in the past two years