generalize CDN list

Some search patterns were too specific to catch all the cases.

Output as Required, since it is, but leave the return value as okay since it could have false positives.

checks/cdn.php

@@ -17,21 +17,22 @@ function check( $php_files, $css_files, $other_files) {
 		checkcount();
 
 		$cdn_list = array(
-			'bootstrap-maxcdn'      => 'maxcdn.bootstrapcdn.com/bootstrap',
-			'bootstrap-netdna'      => 'netdna.bootstrapcdn.com/bootstrap',
-			'bootswatch-maxcdn'     => 'maxcdn.bootstrapcdn.com/bootswatch',
-			'bootswatch-netdna'     => 'netdna.bootstrapcdn.com/bootswatch',
-			'font-awesome-maxcdn'   => 'maxcdn.bootstrapcdn.com/font-awesome',
-			'font-awesome-netdna'   => 'netdna.bootstrapcdn.com/font-awesome',
-			'html5shiv-google'      => 'html5shiv.googlecode.com/svn/trunk/html5.js',
-			'html5shiv-maxcdn'      => 'oss.maxcdn.com/libs/html5shiv',
+			'bootstrap-maxcdn'      => 'maxcdn.bootstrapcdn.com',
+			'bootstrap-netdna'      => 'netdna.bootstrapcdn.com',
+			'bootstrap-stackpath'   => 'stackpath.bootstrapcdn.com',
+			'googlecode'            => 'googlecode.com/svn/',
+			'oss.maxcdn'            => 'oss.maxcdn.com',
 			'jquery'                => 'code.jquery.com/jquery-',
-			'respond-js'            => 'oss.maxcdn.com/libs/respond.js',
+			'aspnetcdn'             => 'aspnetcdn.com',
+			'cloudflare'            => 'cloudflare.com',
+			'keycdn'                => 'keycdn.com',
+			'pxgcdn'                => 'pxgcdn.com',
+			'vimeocdn'              => 'vimeocdn.com',  //usually in JS files
 		);
 
 		foreach( $cdn_list as $cdn_slug => $cdn_url ) {
 			if ( false !== strpos( $all_code, $cdn_url ) ) {
-				$this->error[] = '<span class="tc-lead tc-recommended">' . __('RECOMMENDED','theme-check') . '</span>: ' . sprintf( __( 'Found the URL of a CDN in the code: %s. You should not load CSS or Javascript resources from a CDN, please bundle them with the theme.', 'theme-check' ), '<code>' . esc_html( $cdn_url ) . '</code>' );
+				$this->error[] = '<span class="tc-lead tc-required">' . __('REQUIRED','theme-check') . '</span>: ' . sprintf( __( 'Found the URL of a CDN in the code: %s. You should not load CSS or Javascript resources from a CDN, please bundle them with the theme.', 'theme-check' ), '<code>' . esc_html( $cdn_url ) . '</code>' );
 				//$ret = false;
 			}
 		}