Use `rehash` to get tab completion for $PATH exe's
If you copy an executable into your /usr/local/bin dir you can then run it,
but it doesn't tab complete in zsh. To get tab completion for that new executable without opening a new shell, run rehash.
rehash is not listed in man builtins nor does it have its own man page, but when running which on the command, its listed as a builtin.
> which rehash
rehash: shell built-in command