Fixing some html tags detected as autolinks for diagnostics (#149511)

For markdown such as `<scope:tag>b</scope:tag>`, we currently detect `<scope:tag>` as an uri (an autolink) and then try validating it as a file path

This change doesn't fix `<scope:tag>` being detected as a link (which is actually correct if there isn't closing html), but does fix the us trying to validate it by marking the uri as external

extensions/markdown-language-features/src/languageFeatures/documentLinkProvider.ts

@@ -47,6 +47,11 @@ function parseLink(
 		return { kind: 'external', uri: externalSchemeUri };
 	}
 
+	if (/^[a-z\-][a-z\-]+:/i.test(cleanLink)) {
+		// Looks like a uri
+		return { kind: 'external', uri: vscode.Uri.parse(cleanLink) };
+	}
+
 	// Assume it must be an relative or absolute file path
 	// Use a fake scheme to avoid parse warnings
 	const tempUri = vscode.Uri.parse(`vscode-resource:${link}`);