Prepare for 12.0.0-alpha.5 release (#7166)

Author: cknitt

CHANGELOG.md

@@ -10,7 +10,7 @@
 > - :house: [Internal]
 > - :nail_care: [Polish]
 
-# 12.0.0-alpha.5 (Unreleased)
+# 12.0.0-alpha.5
 
 #### :rocket: New Feature
 
@@ -26,7 +26,7 @@
 
 - Improve code generation for pattern matching of untagged variants. https://github.com/rescript-lang/rescript-compiler/pull/7128
 - Improve negation handling in combination with and/or to simplify generated code (especially coming out of pattern matching). https://github.com/rescript-lang/rescript-compiler/pull/7138
-- optimize JavaScript code generation by using x == null checks and improving type-based optimizations for string/number literals. https://github.com/rescript-lang/rescript-compiler/pull/7141
+- Optimize JavaScript code generation by using `x == null` checks and improving type-based optimizations for string/number literals. https://github.com/rescript-lang/rescript-compiler/pull/7141
 - Improve pattern matching on optional fields. https://github.com/rescript-lang/rescript-compiler/pull/7143 https://github.com/rescript-lang/rescript-compiler/pull/7144
 - Optimize compilation of switch statements for untagged variants when there are no literal cases. https://github.com/rescript-lang/rescript-compiler/pull/7135
 - Further improve boolean optimizations. https://github.com/rescript-lang/rescript-compiler/pull/7149