`git worktree list` when bare repository is named `.git`

["Rebecca Turner" <rbt@fastmail.com>]

It seems that `.git` is always stripped from the `git worktree list` output (including in `--porcelain` mode). This becomes relevant with bare repositories. Here is a bare repository functioning as expected:

$ mkdir bare1
$ cd bare1
$ git init --bare
Initialized empty Git repository in /private/tmp/bare1/
$ git worktree list
/private/tmp/bare1  (bare)

But if we create a bare repository in a directory named `.git`, `git worktree list` displays the parent directory as the worktree, even though `git status` doesn't recognize it as a worktree:

$ mkdir -p bare2/.git
$ cd bare2/.git
$ git init --bare
Initialized empty Git repository in /private/tmp/bare2/.git/
$ git worktree list
/private/tmp/bare2  (bare)
$ cd /tmp/bare2
$ git status
fatal: this operation must be run in a work tree

However, Git _will_ recognize the parent directory (/tmp/bare2) as a Git repository for the purposes of commands like `git rev-parse --git-dir`. I suspect this can be fixed in `get_main_worktree` by only stripping a `.git` suffix from the path if the main worktree is not bare.