Documentation/rtla: rename common_xxx.rst files to common_xxx.txt

Sphinx reports htmldocs errors:

Documentation/tools/rtla/common_options.rst:58: ERROR: Undefined substitution referenced: "threshold".
Documentation/tools/rtla/common_options.rst:88: ERROR: Undefined substitution referenced: "tool".
Documentation/tools/rtla/common_options.rst:88: ERROR: Undefined substitution referenced: "thresharg".
Documentation/tools/rtla/common_options.rst:88: ERROR: Undefined substitution referenced: "tracer".
Documentation/tools/rtla/common_options.rst:92: ERROR: Undefined substitution referenced: "tracer".
Documentation/tools/rtla/common_options.rst:98: ERROR: Undefined substitution referenced: "actionsperf".
Documentation/tools/rtla/common_options.rst:113: ERROR: Undefined substitution referenced: "tool".

common_*.rst files are snippets that are intended to be included by rtla
docs (rtla*.rst). common_options.rst in particular contains
substitutions which depend on other common_* includes, so building it
independently as reST source results in above errors.

Rename all common_*.rst files to common_*.txt to prevent Sphinx from
building these snippets as standalone reST source and update all include
references accordingly.

Link: https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html#substitutions


Suggested-by: Tomas Glozar <tglozar@redhat.com>
Suggested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Gopi Krishna Menon <krishnagopi487@gmail.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Fixes: 05b7e106 ("tools/rtla: Add remaining support for osnoise actions")
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20251008184522.13201-1-krishnagopi487@gmail.com


[Bagas: massage commit message and apply trailers]
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251013092719.30780-2-bagasdotme@gmail.com>