src/vs/workbench/contrib/comments/browser/commentNode.ts/CommentNode/updateCommentBody
class CommentNode:	private updateCommentBody(body: string | IMarkdownString) {
		this._body.innerText = '';
		this._md = undefined;
		this._plainText = undefined;
		if (typeof body === 'string') {
			this._plainText = dom.append(this._body, dom.$('.comment-body-plainstring'));
			this._plainText.innerText = body;
		} else {
			this._md = this.markdownRenderer.render(body).element;
			this._body.appendChild(this._md);
		}
	}