[clang] [clang-format][NFC] Improve KeepFormFeed option decription (PR #176654)

[via cfe-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 85462 tests passed
* 1213 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### Clang
<details>
<summary>Clang.Format/docs_updated.test</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
"/usr/bin/python3" /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Format/../../docs/tools/dump_format_style.py -o /home/gha/actions-runner/_work/llvm-project/llvm-project/build/tools/clang/test/Format/Output/docs_updated.test.tmp.style
# executed command: /usr/bin/python3 /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Format/../../docs/tools/dump_format_style.py -o /home/gha/actions-runner/_work/llvm-project/llvm-project/build/tools/clang/test/Format/Output/docs_updated.test.tmp.style
# note: command had no output on stdout or stderr
# RUN: at line 2
diff --strip-trailing-cr /home/gha/actions-runner/_work/llvm-project/llvm-project/build/tools/clang/test/Format/Output/docs_updated.test.tmp.style    /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Format/../../docs/ClangFormatStyleOptions.rst
# executed command: diff --strip-trailing-cr /home/gha/actions-runner/_work/llvm-project/llvm-project/build/tools/clang/test/Format/Output/docs_updated.test.tmp.style /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Format/../../docs/ClangFormatStyleOptions.rst
# .---command stdout------------
# | *** /home/gha/actions-runner/_work/llvm-project/llvm-project/build/tools/clang/test/Format/Output/docs_updated.test.tmp.style
# | --- /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/Format/../../docs/ClangFormatStyleOptions.rst
# | ***************
# | *** 5014,5023 ****
# |   **KeepFormFeed** (``Boolean``) :versionbadge:`clang-format 20` :ref:`¶ <KeepFormFeed>`
# |     Keep the form feed character (``\f``) if it's immediately preceded and
# |     followed by a newline. Multiple form feeds and newlines within a
# | !   whitespace range are replaced with a single newline and form feed followed
# | !   by the remaining newlines. (See
# | !   https://www.gnu.org/prep/standards/html_node/Formatting.html#:~:text=formfeed
# | !   for more information.)
# |   
# |   .. _LambdaBodyIndentation:
# |   
# | --- 5014,5023 ----
# |   **KeepFormFeed** (``Boolean``) :versionbadge:`clang-format 20` :ref:`¶ <KeepFormFeed>`
# |     Keep the form feed character (``\f``) if it's immediately preceded and
# |     followed by a newline. Multiple form feeds and newlines within a
# | !   whitespace range are replaced with a single newline and form feed
# | !   followed by the remaining newlines. See
# | !   `GNU formfeed coding standard <https://www.gnu.org/prep/standards/html_node/Formatting.html#:~:text=formfeed>`_
# | !   for more information.
# |   
# |   .. _LambdaBodyIndentation:
# |   
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/176654