wp-includes/link-template.php: PhpDoc correction - edit_comment_link() returns void

[Corphi]

Citing wp-includes/link-template.php (line 1003):
* @return string|null HTML content, if $echo is set to false.

should be:
* @return void (or dropped)

The prose should be adapted, too. $echo was probably a parameter to the function that has been removed.

[Corphi]

Variant dropping the return annotation.

[Corphi]

variant using a return void annotation

[nacin]

In 27026:

Docs fix: edit_comment_link() doesn't actually return anything.

props Corphi.
fixes #26436.