Troubleshooting: add tip to check connection to correct remote

Sometimes people fork/clone the wrong repo. We can confirm they have selected the correct one by running

```bash
git remote -v
```

Which should return

```bash
origin	git@github.com:lmu-osc/Collaborative-RStudio-GitHub.git (fetch)
origin	git@github.com:lmu-osc/Collaborative-RStudio-GitHub.git (push)
```