Media: Add support for WebP images in the Thickbox library.

This ensures that `.webp` images are properly recognized and displayed in the modal as expected.

Follow-up to [50810], [51227], [52073].

Props ilunabar, graham73may, sabernhardt, mukesh27, SergeyBiryukov.
Fixes #55786.
Built from https://develop.svn.wordpress.org/trunk@53451


git-svn-id: http://core.svn.wordpress.org/trunk@53040 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/js/thickbox/thickbox.js

@@ -76,10 +76,16 @@ function tb_show(caption, url, imageGroup) {//function called when the user clic
 	   		baseURL = url;
 	   }
 
-	   var urlString = /\.jpg$|\.jpeg$|\.png$|\.gif$|\.bmp$/;
+	   var urlString = /\.jpg$|\.jpeg$|\.png$|\.gif$|\.bmp$|\.webp$/;
 	   var urlType = baseURL.toLowerCase().match(urlString);
 
-		if(urlType == '.jpg' || urlType == '.jpeg' || urlType == '.png' || urlType == '.gif' || urlType == '.bmp'){//code to show images
+		if(urlType == '.jpg' ||
+			urlType == '.jpeg' ||
+			urlType == '.png' ||
+			urlType == '.gif' ||
+			urlType == '.bmp' ||
+			urlType == '.webp'
+		){//code to show images
 
 			TB_PrevCaption = "";
 			TB_PrevURL = "";

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-alpha-53450';
+$wp_version = '6.1-alpha-53451';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.