Replace deprecated $wgSpecialPageGroups

$wgSpecialPageGroups is deprecated since 1.21
override SpecialPage::getGroupName instead

Change-Id: Ia83d3bc0e39bf5d9ea49969c495b81b522e876db

ContributionScores.php

@@ -31,7 +31,6 @@ $wgContribScoreDisableCache = false; // Set to true to disable cache for parser
 
 $wgAutoloadClasses['ContributionScores'] = $dir . 'ContributionScores_body.php';
 $wgSpecialPages['ContributionScores'] = 'ContributionScores';
-$wgSpecialPageGroups['ContributionScores'] = 'wiki';
 
 $wgMessagesDirs['ContributionScores'] = __DIR__ . '/i18n';
 $wgExtensionMessagesFiles['ContributionScores'] = $dir . 'ContributionScores.i18n.php';

ContributionScores_body.php

@@ -248,4 +248,8 @@ class ContributionScores extends IncludableSpecialPage {
 			$out->addHTML( $this->genContributionScoreTable( $days, $revs ) );
 		}
 	}
+
+	protected function getGroupName() {
+		return 'wiki';
+	}
 }