Add missing filters for values in edit-link-category-form.php

[Simek]

Add missing filters ("attribute_escape" and "wp_specialchars") for values in edit-link-category-form.php

is wp_specialchars() suitable within a textarea? (guess yes but I do not properly know).

is the 'editable_slug' filter applicable to be used for category slugs?

if both questions can be answered with yes I think this patch looks good. especially the attribute_escape call is important to prevent injection issues.

unsufficent attribute value escapes are a defect, not an enhancement.

attribute_escape() should become attr() (as in [11109])

see #9650

broken patch

Repaired the patch. Partially this was already fixed in head because of the attr() run by ryan. looks like textareas are missing, I've chosen simeks variant using wp_specialchars() for textarea content.

for textareas, wp has the format_to_edit() sanitizer.

format_to_edit vs. wp_specialchars.

this one is major

format_to_edit for category, tag, and user description

updated patch does the same for tag description and user description.

get_term_to_edit() should take care of the tag description.

get_user_to_edit() could stand to call format_to_edit() instead of wp_specialchars().

Some of the attribute escapes that got added are unnecessary since the *_to_edit() functions should take care of that.

oh right. after double checking, all three cases are processed already. sorry about that.