[PATCH 06/11] worktree.c: add validate_worktree()

This function is later used by "worktree move" and "worktree remove" to ensure that we have a good connection between the repository and the worktree. For example, if a worktree is moved manually, the worktree location recorded in $GIT_DIR/worktrees/.../gitdir is incorrect and we should not move

[PATCH 06/11] worktree.c: add validate_worktree()

This function is later used by "worktree move" and "worktree remove" to ensure that we have a good connection between the repository and the worktree. For example, if a worktree is moved manually, the worktree location recorded in $GIT_DIR/worktrees/.../gitdir is incorrect and we should not move