Apologies, if this has already been reported.
It seems to be impossible to remove a git worktree whose location has
been replaced by the main working tree (don't ask how I found out).
Steps to reproduce:
```
git init test
cd test
git commit --allow-empty -m"Initial commit"
git branch some-branch
git worktree add ../test2 some-branch
cd ../
rm -rf test2 # Remove the worktree folder
mv test test2 # Main git repository now located where the worktree used
to be
```
Afterwards, `git worktree list` reports:
/home/foonathan/test2 e7bb748 [master]
/home/foonathan/test2 e7bb748 [some-branch]
And both `git worktree remove .` and `git worktree remove ../test2`
report an error `fatal: '../test2' is a main working tree`. I had to
manually remove the corresponding folder from `.git/worktree` to get rid
of it. The issue is especially annoying, because you can't check out
`some-branch` anymore (as it's already checked out in the worktree).
I've tested it with git version 2.26.2 and also the version currently on
the next branch.
Thank you,
Jonathan
