Add lang to extended valid elements for span

Resolution to #10505

Author: russellshome

src/Umbraco.Web.UI.Client/src/common/services/tinymce.service.js

@@ -11,7 +11,7 @@ function tinyMceService($rootScope, $q, imageHelper, $locale, $http, $timeout, s
 
     //These are absolutely required in order for the macros to render inline
     //we put these as extended elements because they get merged on top of the normal allowed elements by tiny mce
-    var extendedValidElements = "@[id|class|style],-div[id|dir|class|align|style],ins[datetime|cite],-ul[class|style],-li[class|style],-h1[id|dir|class|align|style],-h2[id|dir|class|align|style],-h3[id|dir|class|align|style],-h4[id|dir|class|align|style],-h5[id|dir|class|align|style],-h6[id|style|dir|class|align],span[id|class|style]";
+    var extendedValidElements = "@[id|class|style],-div[id|dir|class|align|style],ins[datetime|cite],-ul[class|style],-li[class|style],-h1[id|dir|class|align|style],-h2[id|dir|class|align|style],-h3[id|dir|class|align|style],-h4[id|dir|class|align|style],-h5[id|dir|class|align|style],-h6[id|style|dir|class|align],span[id|class|style|lang]";
     var fallbackStyles = [{ title: "Page header", block: "h2" }, { title: "Section header", block: "h3" }, { title: "Paragraph header", block: "h4" }, { title: "Normal", block: "p" }, { title: "Quote", block: "blockquote" }, { title: "Code", block: "code" }];
     // these languages are available for localization
     var availableLanguages = [