Help text not displaying on text area field

Merge request opened. https://git.drupalcode.org/project/label_help/-/merge_requests/5

This also fixes a couple typos, adds variable names to a docblock and fixes this warning which has been popping up:

Warning: Undefined array key "#type" in label_help_form_alter() (line 219 of modules/contrib/label_help/label_help.module).
label_help_form_alter(Array, Object, 'node_event_edit_form') (Line: 562)

Thank you for this module. Digging into the code made me appreciate how difficult this was to implement!

For anyone coming to this issue with the same problem, remember you can get a patch by appending .patch to the end of the merge request URL:
https://git.drupalcode.org/project/label_help/-/merge_requests/5.patch

@maskedjellybean: I'm unable to replicate this issue on a normal Text (formatted, long, with summary) field that exists outside of a field group.

It would be helpful to know which kind of field group config was used, if you happen to know, because there are several permutations that I'll need to test.

I've also tested using the "Fieldset", "Details" and "HTML Element (div)" options from Field Group, and still unable to replicate the issue.

Rebased again on latest 2.0.x branch.

@maskedjellybean: I believe this issue may be resolved by issue 🐛 Avoid clobbering existing field prefix, descriptions, and label suffix values Active where I've completely refactored how the placement logic works.

Unfortunately I'm unable to confirm one way or another because I'm still unable to reproduce this issue.

I would appreciate if you could give that issue a test and if not resolved, write up some more detailed explanation of the field config that is causing the issue here.

Also, I've pulled over one of the commits from your MR here to fix the warning undefined array key #type. I'll rebase this MR shortly.