Don't replace !! in elements
*
55313f4e almost got it right, but missed the str_replacing table
headings.
* Thankfully, this was doubly broken before that patch since the
StringUtils::explodeMarkup would have skipped the || which would
go on to be explode by table cell attribute parsing. The test case
provided would look like,
<table>
<tr>
<th class="">|">ha</div> ho
</th></tr></table>
Suffice it to say, noone is using this in production.
* Note that we can't just entity encode the ! since that would break
style attributes with !important.
* Also note, Parsoid already gets this right.
* Adds a StringUtils::replaceMarkup
Change-Id: Iab3ae4518fcb307b795d57eece420ba48af0a3bf