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

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: vitekn <vitekn@users.noreply.github.com>

Typo fix

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

Co-Authored-By: kaimimue <kaimimue@users.noreply.github.com>

Co-Authored-By: nightgryphon <ngryph@gmail.com>

Co-Authored-By: nightgryphon <ngryph@gmail.com>

* Fix LCD_LANGUAGE options list formatting in config
* Remove 'cn' language option from list

...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

- Respect axis max acceleration limits instead of forcing a fixed acceleration value.
- The `junction_unit_vec` ensures proper handling of entry and exit speeds even when the axes involved have different limits.