parser: Remove unused ParserAfterUnstrip hook

Introduced in 2015 via If83b062. Unfortunately the patch fails to mention
why the hook was introduced. A review comment asking for the missing
information was ignored.

The hook was introduced exclusively for the Cite extension, see I0e136f9.
The Cite change got reverted a few days later via I1a71854. As far as I
can tell the hook (oddly specific and underspecified anyway) was never
used again, neither for Cite nor for anything else.

Now unused: https://codesearch.wmflabs.org/search/?q=ParserAfterUnstrip

I suggest to just remove it with no deprecation phase.

My team is currently working on Cite, essentially turning it upside down.
I'm not aware of a need for this hook.

Change-Id: If68a88d7afff60385ff1e33fd13716b20d01a313

RELEASE-NOTES-1.35

@@ -227,6 +227,7 @@ because of Phabricator reports.
   MediaWikiServices).
 * ApiBase::checkTitleUserPermissions no longer accepts a User as the third
   parameter. Passing a user was deprecated in 1.33.
+* The ParserAfterUnstrip hook was removed without deprecation.
 * …
 
 === Deprecations in 1.35 ===

docs/hooks.txt

@@ -2536,11 +2536,6 @@ $parser: parser object
 $parser: Parser object being used
 &$text: text that will be returned
 
-'ParserAfterUnstrip': Called after the first unstripGeneral() in
-Parser::internalParseHalfParsed()
-$parser: Parser object being used
-&$text: text that will be returned
-
 'ParserBeforeInternalParse': Called at the beginning of Parser::internalParse().
 $parser: Parser object
 &$text: text to parse

includes/parser/Parser.php

@@ -1529,10 +1529,6 @@ class Parser {
 		// Avoid PHP 7.1 warning from passing $this by reference
 		$parser = $this;
 
-		if ( $isMain ) {
-			Hooks::run( 'ParserAfterUnstrip', [ &$parser, &$text ] );
-		}
-
 		# Clean up special characters, only run once, next-to-last before doBlockLevels
 		$text = Sanitizer::armorFrenchSpaces( $text );