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

[Baranov Victor via cfe-commits]

vbvictor 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).

Yes sure! Added summary. Initially thought that patch was already easy enough to understand.

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