[clang-format] Allow a comment to follow a C# attribute specifier

Summary: Add comments to the list of tokens that can follow the ']' at the end of a C# attribute specifier to prevent comments after attribute specifiers from being formatted as continuations.

Reviewers: MyDeveloperDay, krasimir

Reviewed By: MyDeveloperDay

Tags: #clang-format

Differential Revision: https://reviews.llvm.org/D73977