Use fields rather than methods on worktrees

I would prefer to use methods to keep things immutable but I'd rather be consistent with the other
models and update them all at once

pkg/commands/git_commands/worktree_loader.go

@@ -87,7 +87,7 @@ func (self *WorktreeLoader) GetWorktrees() ([]*models.Worktree, error) {
 	}))
 
 	for index, worktree := range worktrees {
-		worktree.NameField = names[index]
+		worktree.Name = names[index]
 	}
 
 	// move current worktree to the top