mediawiki: enable string functions from ParserFunctions

The ParserFunctions extension (which we already use) has some
string functions which I would like to use, but they aren't
enabled by default. Per the documentation, just adding this
config setting should turn them on.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

roles/mediawiki/templates/LocalSettings.php.fp.j2

@@ -312,6 +312,10 @@ wfLoadExtension( 'Interwiki' );
 wfLoadExtension( 'Cite' );
 wfLoadExtension( 'ConfirmEdit' );
 
+# enable string functions from ParserFunctions:
+# https://www.mediawiki.org/wiki/Extension:ParserFunctions
+$wgPFEnableStringFunctions = true;
+
 $wgShowExceptionDetails = true;
 
 $wgSkipSkins = array("chick", "cologneblue", "monobook", "myskin", "nostalgia", "simple", "standard");