Missing clarification of removal of the "view repo" button from the browser extension

Created by: DanielW10001

The "View repository on Sourcegraph" button has been removed at commit 56c6c7, but the button-missing troubleshooting section of the doc does not mention this, and includes "View repository" button as an example.

This can be a bit confusing, especially for those who used to use the "View repository" button, they may think this is a malfunction and follow the rest part of the troubleshooting section.

If we are not adding the "View repository" button back, I suggest we clarify this removal at the beginning of the section. This is trivial so I will just make a PR and if you guys agree you can just merge it.