[texinfo writer] @definfoenclose is discouraged and raises warnings

[mitya57]

Describe the bug

Sphinx uses @definfoenclose command here:

sphinx/sphinx/writers/texinfo.py

Lines 63 to 64 in 20732a3

	@definfoenclose strong,`,'
	@definfoenclose emph,`,'

However the texinfo documentation says:

In practice, there is little use for this command, and we do not recommend you use it. Support for @definfoenclose may be removed in future releases of Texinfo.

And Texinfo prints these warnings when building documentation:

sphinx.texi:18: warning: @definfoenclose is obsolete.
sphinx.texi:19: warning: @definfoenclose is obsolete.

How to Reproduce

$ git clone https://github.com/sphinx-doc/sphinx.git
$ cd sphinx
$ pip install .
$ python ./sphinx/cmd/build.py -b texinfo doc doc/_build/texinfo
$ make -C doc/_build/texinfo info
make: Entering directory '/home/dmitry/upstream/sphinx/_build/texinfo'
makeinfo --no-split -o 'sphinx.info' 'sphinx.texi'
sphinx.texi:18: warning: @definfoenclose is obsolete.
sphinx.texi:19: warning: @definfoenclose is obsolete.
...

Expected behavior

No response

Your project

Reproducible with Sphinx itself

Screenshots

No response

OS

Linux

Python version

3.10

Sphinx version

4.3

Sphinx extensions

No response

Extra tools

No response

Additional context

No response

[tk0miya]

Thank you for your reporting.

Note: I found our docs introcuces a way to customize the style of emphasized texts. So we need to drop the command usage at v5.0.
https://www.sphinx-doc.org/en/master/faq.html#notes

[AA-Turner]

Linked PR was merged.

A