GitHub Pull Request extension in VSC does not fetch GitHub user when tagging with @ in the pull request overview comment section

[chiuarucatalin]

In the GitHub Pull request extension I cannot tag GitHub users with @ on the pull request overview comment section.

• Extension version: 0.120.2
• VSCode Version: 1.105.1
• OS: Windows 11
• Repository Clone Configuration (single repository/fork of an upstream repository): N/A
• GitHub Product (GitHub.com/GitHub Enterprise version x.x.x): GitHub Enterprise Edition

Steps to Reproduce:

1. Open the overview/description part of a pull request
2. Navigate to the comment section at the end and try to put @ in order to tag a specific GitHub.
   As a result there is no user fetch happening. On the other hand, if you know the GitHub User by heart and you type in after adding and saving the comment the user is transformed in an hyperlink and connected to the real GitHub user.