wp_insert_comment better docstrings

[lamosty]

Function wp_insert_comment has incomplete docstring documentation. Its docstring says

The available comment data key names are 'comment_author_IP', 'comment_date',
'comment_date_gmt', 'comment_parent', 'comment_approved', and 'user_id'.

but the function accepts additional arguments through $commentdata assoc array, such as comment_type or comment_content.

Docstring could be enhanced to have a format like in the case of wp_insert_post function (=> argument type with a short description of what the argument does).

[lamosty]

Update docs of wp_insert_comment function

[rachelbaker]

Minor formatting and description adjustments

[DrewAPicture]

In 32499:

Document the default arguments for wp_insert_comment() as a hash notation.

Props lamosty, rachelbaker.
See #31747.

[DrewAPicture]

In 32500:

Update the DocBlock for wp_new_comment() to reference the wp_insert_comment() documentation for argument information.

Fixes #31747.