Building the epub version of the docs results in an invalid epub with errors on pages with console directives

[Natalia Bidart]

While working on #37138, I tested the epub build and it generates an epub file where the pages including console directives show unexpected content.

For example, in an online epub reader (​https://epub-reader.online/):

XML Parsing Error: not well-formed Location: https://epub-reader.online/# Line Number 31, Column 82:<input class="c-tab-unix" id="c-tab-0-unix" type="radio" name="console-0" checked> ---------------------------------------------------------------------------------^

Locally with calibre the two OS radio buttons are shown as shown in this attached image:

[Sarah Boyce <42296566+sarahboyce@…>]

In c087b7e8:

Fixed #37204 -- Rendered console directives as plain code in epub docs builds.

The console directive renders its Unix/Windows tabs with browser-only
markup: hidden radio inputs toggled via CSS. The epub builder shares the
HTML format, so it copied that markup into the ebook, where the tabs
cannot work (e-readers do not support the driving CSS) and the raw HTML
is not well-formed XHTML, so strict readers fail to parse the page.

Skipped the tab markup for the epub builder and fell back to a plain
literal block, matching what the non-HTML builders already do.