Examples using the keypad module for a keyboard and macros

We could use [an] example[s] that uses the `keypad` module for a keyboard, and shortcuts or macros.
Mention to @kattni as promised.

Possibly showing concepts like:
- use `event.pressed` to trigger a keyboard send or a layout write.
- use `pressed`/`released` to hold a key while the button is down (like a real keyboard).

Maybe more advanced:
- use a state variable to toggle a key on/off on button press. (That question comes up from time to time).

No file or test is named. Start by locating the keypad module and the repository's existing example structure, then review how keyboard sends and layouts are demonstrated. Done means adding examples for pressed events, held keys with pressed/released, and a state-based toggle or macro.

Written by the indexing model from the issue text.