Clean up document link resolve (#154959)

- Move vscode scheme normalization to the DocumentLinkProvider
- Remove extra function since we already recognize uri-like links

extensions/markdown-language-features/src/util/schemes.ts

@@ -3,33 +3,15 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import * as vscode from 'vscode';
-
 export const Schemes = Object.freeze({
-	http: 'http',
-	https: 'https',
 	file: 'file',
 	untitled: 'untitled',
 	mailto: 'mailto',
-	data: 'data',
 	vscode: 'vscode',
 	'vscode-insiders': 'vscode-insiders',
 	notebookCell: 'vscode-notebook-cell',
 });
 
-const knownSchemes = [
-	...Object.values(Schemes),
-	`${vscode.env.uriScheme}`
-];
-
-export function getUriForLinkWithKnownExternalScheme(link: string): vscode.Uri | undefined {
-	if (knownSchemes.some(knownScheme => isOfScheme(knownScheme, link))) {
-		return vscode.Uri.parse(link);
-	}
-
-	return undefined;
-}
-
 export function isOfScheme(scheme: string, link: string): boolean {
 	return link.toLowerCase().startsWith(scheme + ':');
 }