Turn the checkbox-lists of supported platforms and languages into normal bullet lists

[jmacdotorg]

https://docs.coderabbit.ai/finishing-touches/docstrings/?#supported-software-forges

The use of checkboxes (in two states!) as bullets on the lists on this page is a little ambiguous. It isn't clear what an unchecked item means. I am told it means that the language exists but isn't supported, but that invites the question of how is that different from an existing, unsupported language that isn't listed here at all.

Let's remove all the unchecked items, and then replace the checkboxes with normal bullets.

[linear]

ENG-1417 Turn the checkbox-lists of supported platforms and languages into normal bullet lists