[clang] [clang][transformer] Allow usage of applyFirst with rewriteDescendants (PR #117658)

[Yitzhak Mandelbaum via cfe-commits]

ymand wrote:

> Without these changes a clash appears between a Tag, which is bound to enclosing match, and a Tag, which is associated with first Case of applyFirst in rewriteDescendands.

Can you expand on your concern about the clash? Your approach of using the matcher ID seems like an improvement, but I'm not clear on what exactly we're trying to avoid.

https://github.com/llvm/llvm-project/pull/117658