Same markdown writing experience as GH

Would be nice if the description field for new PRs supported the same keyboard shortcuts as textareas on GitHub.

In particular, I'm missing the ability to hit cmd + e or the backtick key with text selected to surround it with backticks:

On GitHub with "this" selected and hitting cmd + e or hitting `, I get this.

In vscode-pull-request-github, I get nothing/the selection is replaced by `.

从 vscode-pull-request-github 中新 pull request 的描述字段开始，使用选中的文本和 backtick 或 cmd+e 快捷键复现所报告的行为。跟踪现有的 textarea 或编辑器入口，然后验证选中的文本会被 backticks 包围，而不会被替换。