Add optional simple markdown support to PlainTextRenderer for inline code

Co-authored-by: alexr00 <38270282+alexr00@users.noreply.github.com>

Author: Copilot

src/github/copilotRemoteAgent/chatSessionContentBuilder.ts

@@ -76,7 +76,7 @@ export class ChatSessionContentBuilder {
 				// if this is the first response, then also add the PR card
 				if (sessionIndex === 0) {
 					const uri = await toOpenPullRequestWebviewUri({ owner: pullRequest.remote.owner, repo: pullRequest.remote.repositoryName, pullRequestNumber: pullRequest.number });
-					const plaintextBody = marked.parse(pullRequest.body, { renderer: new PlainTextRenderer(), smartypants: true }).trim();
+					const plaintextBody = marked.parse(pullRequest.body, { renderer: new PlainTextRenderer(true), smartypants: true }).trim();
 
 					const card = new vscode.ChatResponsePullRequestPart(uri, pullRequest.title, plaintextBody, pullRequest.author.specialDisplayName ?? pullRequest.author.login, `#${pullRequest.number}`);
 					const cardTurn = new vscode.ChatResponseTurn2([card], {}, COPILOT_SWE_AGENT);

src/github/markdownUtils.ts

@@ -237,6 +237,13 @@ export async function issueMarkdown(
 }
 
 export class PlainTextRenderer extends marked.Renderer {
+	private allowSimpleMarkdown: boolean;
+
+	constructor(allowSimpleMarkdown: boolean = false) {
+		super();
+		this.allowSimpleMarkdown = allowSimpleMarkdown;
+	}
+
 	override code(code: string, _infostring: string | undefined): string {
 		return code;
 	}
@@ -286,6 +293,9 @@ export class PlainTextRenderer extends marked.Renderer {
 		return text;
 	}
 	override codespan(code: string): string {
+		if (this.allowSimpleMarkdown) {
+			return `\`${code}\``;
+		}
 		return `\\\`${code}\\\``;
 	}
 	override br(): string {

src/test/github/markdownUtils.test.ts

@@ -0,0 +1,34 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as assert from 'assert';
+import * as marked from 'marked';
+import { PlainTextRenderer } from '../../github/markdownUtils';
+
+suite('PlainTextRenderer', () => {
+	test('should escape inline code by default', () => {
+		const renderer = new PlainTextRenderer();
+		const result = marked.parse('rename the `Foo` class', { renderer, smartypants: true });
+		assert.strictEqual(result.trim(), 'rename the \\`Foo\\` class');
+	});
+
+	test('should preserve inline code when allowSimpleMarkdown is true', () => {
+		const renderer = new PlainTextRenderer(true);
+		const result = marked.parse('rename the `Foo` class', { renderer, smartypants: true });
+		assert.strictEqual(result.trim(), 'rename the `Foo` class');
+	});
+
+	test('should handle multiple inline code spans', () => {
+		const renderer = new PlainTextRenderer(true);
+		const result = marked.parse('rename the `Foo` class to `Bar`', { renderer, smartypants: true });
+		assert.strictEqual(result.trim(), 'rename the `Foo` class to `Bar`');
+	});
+
+	test('should still escape when allowSimpleMarkdown is false', () => {
+		const renderer = new PlainTextRenderer(false);
+		const result = marked.parse('rename the `Foo` class to `Bar`', { renderer, smartypants: true });
+		assert.strictEqual(result.trim(), 'rename the \\`Foo\\` class to \\`Bar\\`');
+	});
+});