Toggle Line Comment in Fenced code blocks for LaTeX doesn't work well

[yarakos95]

This problem still occurs even if you disable all extensions and occurs in both stable and insider.

Demonstration

Create the following Fenced code blocks for LaTeX in Markdown file.

```latex
\documentclass{article}
\begin{document}
    Hello, \LaTeX{}!!
\end{document}
```

Then run Toggle Line Comment (Ctrl+/) on the line with Hello, \LaTeX{}!!.
You will get the following results:

```latex
\documentclass{article}
\begin{document}
    <!-- Hello, \LaTeX{}!! -->
\end{document}
```

The correct result is:

```latex
\documentclass{article}
\begin{document}
    % Hello, \LaTeX{}!!
\end{document}
```

GIF animation

Execute Ctrl+/ repeatedly

Version

 Version: 1.67.2 (user setup)
  Commit: c3511e6c69bb39013c4a4b7b9566ec1ca73fc4d5
    Date: 2022-05-17T18:15:52.058Z
Electron: 17.4.1
Chromium: 98.0.4758.141
 Node.js: 16.13.0
      V8: 9.8.177.13-electron.0
      OS: Windows_NT x64 10.0.19043

 Version: 1.68.0-insider (user setup)
  Commit: c0769274fa136b45799edeccc0d0a2f645b75caf
    Date: 2022-05-23T05:17:12.256Z
Electron: 17.4.4
Chromium: 98.0.4758.141
 Node.js: 16.13.0
      V8: 9.8.177.13-electron.0
      OS: Windows_NT x64 10.0.19043

[nerdjfpb]

Hi @Yarakashi-Kikohshi
Did you save the file? I disabled all my extensions for vscode insider and can't reproduce this issue.

Is this still happening for you?

[yarakos95]

@nerdjfpb

Did you save the file?

Yes. And all extensions are disabled.

Is this still happening for you?

Yes.

---

The insider was updated to the following versions because has been available for updating. However, the problem continues to be reproduced.

 Version: 1.68.0-insider (user setup)
  Commit: 2260d7cca34384a2838c728850afdd38113ddb47
    Date: 2022-06-04T00:31:50.829Z
Electron: 17.4.6
Chromium: 98.0.4758.141
 Node.js: 16.13.0
      V8: 9.8.177.13-electron.0
      OS: Windows_NT x64 10.0.19043

[nerdjfpb]

@nerdjfpb

Did you save the file?

Yes. And all extensions are disabled.

Is this still happening for you?

Yes.

The insider was updated to the following versions because has been available for updating. However, the problem continues to be reproduced.

 Version: 1.68.0-insider (user setup)
  Commit: 2260d7cca34384a2838c728850afdd38113ddb47
    Date: 2022-06-04T00:31:50.829Z
Electron: 17.4.6
Chromium: 98.0.4758.141
 Node.js: 16.13.0
      V8: 9.8.177.13-electron.0
      OS: Windows_NT x64 10.0.19043

Sorry I was saving file as latex extension so it worked. I tried with markdown and it doesn't work for me too. This is a verified bug now.

[Priyankcoder]

@mjbvz Hi, I'm having the same issue. I'm new to the codebase. Can I try to solve this issue?

[yarakos95]

@nerdjfpb @Priyankcoder

I had previously submitted similar issue. It may help to solve this issue. See #142960.

[Priyankcoder]

@Yarakashi-Kikohshi thanks for this, It will help me solve this issue. I am working on this.

[Priyankcoder]

Hey @mjbvz, I made the PR. Could you please check it?