main
update headers
Copilot: Fix culture-sensitive StringBuilder.Append and ToString calls across codebase and add banned symbols (#80800)
Extensions: DocumentationCommentId and ExtensionGroupingName/ExtensionMarkerName APIs, update grouping type metadata name (#80164)
Fix symbol display for backing fields (#76000)
Fix handling of SymbolDisplayCompilerInternalOptions.UseArityForGenericTypes option for non-native symbol implementations (#80826)
Merge branch 'main' into fix-66009
Rename new properties to PascalCase