Availability extension's text translation breaks directive rendering

Documentation

The availability extension shows "Availability" text in the built docs. In the translation context, "Availability" is available for translation, but translating that text causes hundreds of warnings like this:

Warning: /path/to/cpython/Doc/library/os.rst:181: WARNING: inconsistent term references in translated message. original: ['Availability'], translated: [] [i18n.inconsistent_references]

The translated page will show the translation text ("Disponibilidade", in Portuguese) without the important text: the platforms where it is available. (That's unwanted!)

Some checking around:

• In original English, os.ctermid() shows "Availability: Unix, not WASI.". See source file Doc/library/os.rst
• In Brazilian Portuguese, os.ctermid() shows "Disponibilidade" but without the plataforms and without the hyperlink. See the string in the translation file (library/os.po)
• in Simplified Chinese, I see in os.ctermid() they translated keeping "Availability" in English to escape this issue 😁. See the string in the translation file (library/os.po)

Linked PRs

• gh-126609: Revert commit cbfd3924 to fix errors #129479
• gh-126609: Revert Availability Directive changes #129480
• gh-126609: docs: revert changes made to the internal structure of availability directive #129482
• gh-126609: Allow translating the availability directive #129549
• [3.13] gh-126609: Allow translating the availability directive (GH-129549) #129584
• [3.12] gh-126609: Allow translating the availability directive (GH-129549) #129585
• gh-126609: localize list, allow translation of a phrase, use ge operator character in the availability directive #129597