[clang-format][NFC] Fix broken dump_format_help.py and sync RST file (#65429)

Running `dump_format_help.py` in `clang/docs/tools`:
```
warning: line too long:
                                      relative to the current working directory when reading stdin.
warning: line too long:
     --files=<filename>             - A file containing a list of files to process, one per line.
warning: line too long:
     --help-list                    - Display list of available options (--help-list-hidden for more)
Traceback (most recent call last):
  File "/Users/Owen/remove-braces/clang/docs/tools/./dump_format_help.py", line 63, in <module>
    contents = substitute(contents, "FORMAT_HELP", help_text)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/Owen/remove-braces/clang/docs/tools/./dump_format_help.py", line 17, in substitute
    return re.sub(pattern, "%s", text, flags=re.S) % replacement
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
TypeError: not enough arguments for format string
```