[llvm] [gitattributes] Mark some llvm-rc inputs as requiring LF newlines (PR #113222)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

Also, for context - see https://github.com/mstorsjo/llvm-project/actions/runs/11478930901/job/31944142725 for a list of other remaining failing tests if we'd do a fresh checkout with CRLF newlines. We have these two failing:
```
  Clang Tools :: clang-move/move-used-helper-decls.cpp
  lit :: shtest-shell.py
```
Plus 73 Clang tests failing.

https://github.com/llvm/llvm-project/pull/113222