Add fallback getDescription method for MW < 1.41 compat

Fixes: #191

Author: alistair3149

src/EntryPoints/SpecialWikibaseExport.php

@@ -38,8 +38,15 @@ public function getGroupName(): string {
 		return 'wikibase';
 	}
 
-	public function getDescription(): Message {
-		return $this->msg( 'special-wikibase-export' );
+	/**
+	 * @return string|Message Returns string in MW < 1.41 and Message in MW >= 1.41
+	 */
+	public function getDescription() {
+		if ( version_compare( MW_VERSION, '1.41', '>=' ) ) {
+			return $this->msg( 'special-wikibase-export' );
+		} else {
+			return $this->msg( 'special-wikibase-export' )->escaped();
+		}
 	}
 
 	private function shouldShowConfigLink(): bool {

src/EntryPoints/SpecialWikibaseExportConfig.php

@@ -4,6 +4,7 @@
 
 namespace ProfessionalWiki\WikibaseExport\EntryPoints;
 
+use Message;
 use SpecialPage;
 use Title;
 
@@ -27,8 +28,15 @@ public function getGroupName(): string {
 		return 'wikibase';
 	}
 
-	public function getDescription(): string {
-		return $this->msg( 'special-wikibase-export-config' )->escaped();
+	/**
+	 * @return string|Message Returns string in MW < 1.41 and Message in MW >= 1.41
+	 */
+	public function getDescription() {
+		if ( version_compare( MW_VERSION, '1.41', '>=' ) ) {
+			return $this->msg( 'special-wikibase-export-config' );
+		} else {
+			return $this->msg( 'special-wikibase-export-config' )->escaped();
+		}
 	}
 
 }