[DOCS] Document usage of "htmlSupport" option in EXT:rte_ckeditor

Additionally:
- Use "page TSconfig" over "Page TSconfig"
- Add captions to make clearer where to store the configuration as an example

Resolves: #102126
Resolves: https://github.com/TYPO3-Documentation/Changelog-To-Doc/issues/686
Related: #99738
Releases: main, 12.4
Change-Id: I983a9411c3c30ddf040eba0c296a2bee6c0ab509
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/81383


Reviewed-by: Torben Hansen <derhansen@gmail.com>
Tested-by: Torben Hansen <derhansen@gmail.com>
Tested-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>