It probably wasn't included originally, as its not part of html4,
but was introduced in XML/XHTML1. Since we do all sorts of weird stuff
with ' characters (italic/bold) its probably good to allow lowly users to
have an easy to remember way of escaping it.
There's also a whole bunch of entities in html5 that we should maybe consider
decoding as well.
* (bug 28372) Fix bogus link to suppressed file versions in ForeignDBRepo
* (bug 27473) Fix regression: bold, italic no longer interfere with linktrail for ca, kaa
* (bug 28444) Fix regression: edit-on-doubleclick retains revision id again
+* ' character entity is now allowed in wikitext
=== API changes in 1.18 ===
* (bug 26339) Throw warning when truncating an overlarge API result
/**
* List of all named character entities defined in HTML 4.01
* http://www.w3.org/TR/html4/sgml/entities.html
+ * As well as ' which is only defined starting in XHTML1.
* @private
*/
static $htmlEntities = array(
'amp' => 38,
'and' => 8743,
'ang' => 8736,
+ 'apos' => 39,
'Aring' => 197,
'aring' => 229,
'asymp' => 8776,