Co-Authored-By: dot-bob <gibben@gmail.com>

Indeed the HAL does not need to be mucked around with to expose ATmega2560 pins not available as numbers on the MEGA board, I'll need to update the wiki with that tidbit and a reference to the pin-mapping comment in `fastio_1280.h`.

Co-Authored-By: teemuatlut <teemu.mantykallio@live.fi>

* Add Multi Unit Support for Max7219 to bugfix_2.0.0

* Apply multi-MAX7219 to example configs

* Tweak some spacing, macros

...and recommended pulse width configuration for A4988

The timing value should be properly set for ALL boards. The compiler will check and set maximum step rate calculations based on those values.

- Stepper bugs fixed
- Support MIXING_EXTRUDER with Linear Advance
- Miscellaneous cleanup

Part of #10688

Co-Authored-By: ejtagle <ejtagle@hotmail.com>

Some users may prefer to hide the position updates on the `LIGHTWEIGHT_UI` altogether. This leads to an even less cluttered display (it also saves on SPI traffic and one byte of RAM).