git-gui: add gui and pick as explicit subcommands
git-gui accepts subcommands blame | browser | citool, and assumes the subcommand is 'gui' if none is actually given, But, git-gui also has a repository picker (choose_repository::pick) that can create a new repository + worktree, or choose an existing one, switch to that, and the run the gui. The user has no direct control over invoking the picker, instead the picker is triggered by failure in the repository / worktree discovery process: this includes being started in a directory not controlled by git, which is probably the intended use case. The picker can appear when the user has no intention of creating a new worktree, and the user cannot use the picker to create a new worktree inside another. So, add two explicit subcommands: gui - Run the gui if repository/worktree discovery succeeds, or die with an error message, but never run the picker. pick - First run the picker, regardless, then start the gui in the chosen worktree. Nothing in this changes the prior behavior, the alternates above must be explicitly selected to see any change. Signed-off-by: Mark Levedahl <mlevedahl@gmail.com> Signed-off-by: Johannes Sixt <j6t@kdbg.org>