[clang-format] NFC allow Format.h to be clang-formatted but still maintain the same...

[clang-format] NFC allow Format.h to be clang-formatted but still maintain the same doc layout in ClangFormatStyleOptions.rst

Summary:
Format.h is used to generate ClangFormatStyleOptions.rst, the layout of the comments is critical to the rst file. Accidentally clang-formatting Format.h can lead to the .rst changing.

This revision simply add // clang-format off/on statement around the areas who formatting needs to be maintained, mainly around the options that are related to what happens when the line breaks due to `ColumnLimit` (which is what is happening to the comment)

This allows Format.h to be clang-formatted without causing a change in the documentation when dump_format_style.py is rerun, which is also part of the revision.

Reviewers: mitchell-stellar, klimek, sammccall, owenpan

Reviewed By: mitchell-stellar

Subscribers: cfe-commits

Tags: #clang, #clang-format

Differential Revision: https://reviews.llvm.org/D69951