planner.h:
fan speed is used to set integer variables, so no need for long.
Basicaly a byte should be enough for all the fan things, as it's 0-255?

planner.cpp:
Save some float multiplications.
We could squeeze out even more by defining feedrate_percentage,
saved_feedrate_percentage and flow_percentage as float instead of int.
Everytime they are used in the time-critical planner, they are casted to
float and multiplied by 0.01. Not done jet, as they are used in LCD menu
functions I don't know well enough.

The flag is already set inside planner.get_current_block(). Doing it
twice isn't making it better..

・Update forgotten K8400\Dual-head\Configuration.h
・Adjust spacing

・Add new translation

・Remove all the #ifndef
・Follow the PR #4603 (Strip never-translated strings from language
files)
・Follow the PR #4634 (Set language display charset in language.h)
・Follow the PR #4936 (Put max_jerk vars in array, clean up jerk code)
・Adjust spacing

Add optional parameters
X, Y for probe point
S sets stowing on and off

Added a rule so that LIN_ADVANCE isn't used for moves with negative E movements (de_float will be negative in this cases).
I also added a more detailed comment to make it more clear what the if statement does.

- Allow more than 9x9 probe points
- Account for the probe starting position

bool feedback is no longer used

・Add CASE_LIGHT_PIN into pinsDebug.h

implemented G-Code M355 into Marlin

The extrusion speed was wrong due to a not high enough precision of
esteps to XY steps, therefore now the target float values are used to
calculate the ratio between XY movement and extrusion speed.
The e_speed_multiplier8 was replaced by an absolute multiplier called
abs_adv_steps_multiplier8, therefore one multiplication and bitshift can
be saved inside the stepper ISR. Due to this, also extruder_advance_k is
better suited inside the planner and not the stepper files any more.

see detailed  description in PR #5118