Use content language as default language for ime selector

Change-Id: I9780cefc6585ebcc99bd8a45ccf10ecf6ee54a4d

resources/js/ext.uls.ime.js

@@ -95,7 +95,11 @@
 			} else {
 				return this.registry.enable;
 			}
-		}
+		},
+
+		getDefaultLanguage: function () {
+			return mw.config.get( 'wgContentLanguage' );
+		},
 	} );
 
 	// MediaWiki specific overrides for jquery.ime