build: Updating mediawiki/mediawiki-phan-config to 0.20.0

Change-Id: Iedcdc14f60a7a7a3c49e02888d6fcb2ec022dd63

Author: umherirrender

composer.json

@@ -45,7 +45,7 @@
 	},
 	"require-dev": {
 		"mediawiki/mediawiki-codesniffer": "50.0.0",
-		"mediawiki/mediawiki-phan-config": "0.19.0",
+		"mediawiki/mediawiki-phan-config": "0.20.0",
 		"mediawiki/minus-x": "2.0.1",
 		"php-parallel-lint/php-console-highlighter": "1.0.0",
 		"php-parallel-lint/php-parallel-lint": "1.4.0",

lib/Less/Tree/Mixin/Definition.php

@@ -106,7 +106,6 @@ public function compileParams( $env, $mixinFrames, $args = [], &$evaldArguments
 					$expression = new Less_Tree_Expression( $varargs );
 					array_unshift( $frame->rules, new Less_Tree_Declaration( $name, $expression->compile( $env ) ) );
 				} else {
-					// @phan-suppress-next-line PhanTypePossiblyInvalidDimOffset
 					$val = ( $arg && $arg['value'] ) ? $arg['value'] : false;
 
 					if ( $val ) {