[clang] [clang-tools-extra] [ASTMatchers] Make isExpandedFromMacro accept llvm::StringRef (PR #167060)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

Please add a summary to the PR (the summary ends up becoming the commit message, so we want them to be informative as to why the changes are needed).

https://github.com/llvm/llvm-project/pull/167060