Use namespaced imports

Also bumps MW requirement to 1.40 as the namespaces were introduced in that version.
Remove unnecessary GROUP BY, which causes errors in MySQL strict mode.

Change-Id: I9cfc32b13518da39b97662e424682d4d7a7cf862

extension.json

@@ -6,7 +6,7 @@
 	"version": "1.26.1",
 	"type": "specialpage",
 	"requires": {
-		"MediaWiki": ">= 1.34.0"
+		"MediaWiki": ">= 1.40.0"
 	},
 	"SpecialPages": {
 		"ContributionScores": "ContributionScores"

src/ContributionScores.php

@@ -3,7 +3,10 @@
  * \brief Contains code for the ContributionScores Class (extends SpecialPage).
  */
 
+use MediaWiki\Html\Html;
+use MediaWiki\Linker\Linker;
 use MediaWiki\MediaWikiServices;
+use MediaWiki\User\ActorMigration;
 
 /// Special page class for the Contribution Scores extension
 /**
@@ -187,7 +190,6 @@ class ContributionScores extends IncludableSpecialPage {
 			__METHOD__,
 			[
 				'ORDER BY' => 'wiki_rank DESC',
-				'GROUP BY' => 'user_name',
 				'LIMIT' => $limit,
 			],
 			[