[PATCH 10/11] worktree move: refuse to move worktrees with submodules

Submodules contains .git files with relative paths. After a worktree move, these files need to be updated or they may point to nowhere. This is a bandage patch to make sure "worktree move" don't break people's worktrees by accident. When .git file update code is in place, this validate_no_submodul

[PATCH 10/11] worktree move: refuse to move worktrees with submodules

Submodules contains .git files with relative paths. After a worktree move, these files need to be updated or they may point to nowhere. This is a bandage patch to make sure "worktree move" don't break people's worktrees by accident. When .git file update code is in place, this validate_no_submodul