Finalize asWebviewUri api

Fixes #79242

As discussed, renames `toWebviewResource` to `asWebviewUri` to be consistent with the `asAbsolutePath` api naming

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

@@ -6,7 +6,7 @@
 import * as vscode from 'vscode';
 
 export interface WebviewResourceProvider {
-	toWebviewResource(resource: vscode.Uri): vscode.Uri;
+	asWebviewUri(resource: vscode.Uri): vscode.Uri;
 
 	readonly cspSource: string;
 }
@@ -30,4 +30,4 @@ export function normalizeResource(
 		}
 	}
 	return resource;
-}
+}