[clang] [llvm] [clang-format] Add cmake target clang-format-style-options for updating ClangFormatStyleOptions.rst (PR #111513)

[Owen Pan via cfe-commits]

owenca wrote:

> ```
> FAILED: /var/llvm-compile-time-tracker/llvm-project/clang/docs/ClangFormatStyleOptions.rst 
> cd /var/llvm-compile-time-tracker/llvm-project/clang/docs/tools && /usr/bin/python3.10 dump_format_style.py
> Traceback (most recent call last):
>   File "/var/llvm-compile-time-tracker/llvm-project/clang/docs/tools/dump_format_style.py", line 23, in <module>
>     with open(PLURALS_FILE, "a+") as f:
> PermissionError: [Errno 13] Permission denied: '/var/llvm-compile-time-tracker/llvm-project/clang/docs/tools/plurals.txt'
> ```

Changed the mode to read-only in 74d29c6393df606e98e7c42b9a97f56f335e3ffb.

https://github.com/llvm/llvm-project/pull/111513