This commit also adds means to manually disable warnings
in `code` tags where it's a false positive with the new
`skip-lint` attribute.
Warnings are now enabled on CI to prevent future errors.
Also:
* changed `[b]true[/b]` to `[code]true[/code]`
* use `[i]` for mathematical constant "e"
* use `[b]` for button text & menu item text
* improve markups about "tap1" and "tap2" in AudioEffectDelay
We don't use that info for anything, and it generates unnecessary diffs
every time we bump the minor version (and CI failures if we forget to
sync some files from opt-in modules (mono, text_server_fb).
