Use native str_contains/str_starts_with in a few more places

This makes the code quit a bit more readable, I believe.

Change-Id: I4aef30d5e20d095c421a13ad5104d64c71361c88

includes/FontRepoCompiler.php

@@ -99,7 +99,7 @@ class FontRepoCompiler {
 				$languages[$code] = [ 'system' ];
 			}
 
-			if ( strpos( $rcode, '*' ) !== false ) {
+			if ( str_contains( $rcode, '*' ) ) {
 				if ( $languages[$code][0] === 'system' ) {
 					unset( $languages[$code][0] );
 				}