Make documentation more consistent with Vim's own :help

[frdr]

Some improvements to ALE's documentation, mainly to make it look and work more like Vim's own :help pages. There were no changes in content (I hope) and no code changes (my excuse for not writing any tests).

The following items were changed:

• prefix user-defined commands with a colon
• prefix highlight groups with "hl-"
• the two items above naturally disambiguate :ALEInfo from hl-ALEInfo; I retired the ALEInfo. (trailing dot) tag
• use backticks for :commands, single quotes for 'options', plus signs for +features and pipes for |anything| else, except where it would have made things worse
• fix some dead hotlinks, e.g. loclist to location-list; the latter one will actually work
• mention optional [args] to commands where they can be given
• formatting changes where space ran out due to the changes above

The whole thing started when I typed :help :ALEFix (note the colon before the command) and found nothing. With these changes, both this and :help ALEFix (no colon) will jump to the right place.

Keep up the good work and cheers!

[hsanson]

There seem to be some align issues witht the help tags:

• https://github.com/dense-analysis/ale/actions/runs/11193354235/job/31477165279?pr=4840#step:3:41

[frdr]

Sorry for that oversight. I fixed tag alignment and all tests pass locally. Give it another try. Thanks.