Merge pull request #83320 from lorentey/utils-codeowners

[meta] Set stdlib team as codeowners on availability macros & gyb

Author: lorentey

.github/CODEOWNERS

@@ -291,10 +291,16 @@
 
 # utils
 /utils/*windows* @compnerd
+/utils/availability-macros.def @swiftlang/standard-librarians
 /utils/build.ps1 @compnerd
 /utils/build_swift/ @etcwilde @justice-adams-apple @shahmishal
 /utils/generate-xcode @hamishknight
+/utils/gen-unicode-data @swiftlang/standard-librarians
+/utils/gyb @swiftlang/standard-librarians
+/utils/gyb_foundation_support.py @swiftlang/standard-librarians
 /utils/gyb_sourcekit_support/ @bnbarham @hamishknight @rintaro
+/utils/gyb_stdlib_support.py @swiftlang/standard-librarians
+/utils/gyb.py @swiftlang/standard-librarians
 /utils/sourcekit_fuzzer/ @bnbarham @hamishknight @rintaro
 /utils/swift-xcodegen/ @hamishknight
 /utils/swift_build_support/ @etcwilde @justice-adams-apple @shahmishal