[html] update service and fix url resolving (#155725)

extensions/html-language-features/server/src/utils/documentContext.ts

@@ -24,6 +24,10 @@ export function getDocumentContext(documentUri: string, workspaceFolders: Worksp
 
 	return {
 		resolveReference: (ref: string, base = documentUri) => {
+			if (ref.match(/^\w[\w\d+.-]*:/)) {
+				// starts with a schema
+				return ref;
+			}
 			if (ref[0] === '/') { // resolve absolute path against the current workspace folder
 				const folderUri = getRootFolder();
 				if (folderUri) {