Update SRF_Calendar.php (#929)

* Update SRF_Calendar.php

first day of week issue
#138

* Update SRF_Calendar.php

Fix phpcs issue

---------

Co-authored-by: jaideraf <jaideraf@gmail.com>

Author: krabina

formats/calendar/SRF_Calendar.php

@@ -393,7 +393,7 @@ public function displayCalendar( $events ) {
 			$lastDayOfWeek = 7;
 		} else {
 			$firstDayOfWeek =
-				array_search( $srfgFirstDayOfWeek, $weekDayNames );
+				array_search( wfMessage( $srfgFirstDayOfWeek )->text(), $weekDayNames );
 			if ( $firstDayOfWeek === false ) {
 				// Bad value for $srfgFirstDayOfWeek!
 				print 'Warning: Bad value for $srfgFirstDayOfWeek "' .