Made the double touch portion a conditional compile based on the
PROBE_DOUBLE_TOUCH flag.

==============================================

Bugfix

The current G38 only stopped a move if it involved the Z axis.

Moved all the G38 code to it's own section and put it where it would
always be executed no matter what axis was moving or if the endstop was
enabled.

Also added a comment to configuration_adv to alert the user the double
tap had to be turned on.

==============================================

Change G38 back to using Z_MIN_PROBE

There's no Z_MIN endstop if Z_DUAL_ENDSTOPS is enabled and you have them
set to the top of the gantry.

G38 started out as using the Z_MIN_PROBE pin.  I don't remember why we
changed it to the Z_MIN endstop.

Work around for slicers producing buggy gcode.

The target here is to update the screens of graphical and char base
displays as fast as possible, without draining the planner buffer too much.

For that measure the time it takes to draw and transfer one
(partial) screen to the display. Build a max. value from that.
Because ther can be large differences, depending on how much the display
updates are interrupted, the max value is decreased by one ms/s. This way
it can shrink again.
On the other side we keep track on how much time it takes to empty the
planner buffer.
Now we draw the next (partial) display update only then, when we do not
drain the planner buffer to much. We draw only when the time in the
buffer is two times larger than a update takes, or the buffer is empty anyway.

When we have begun to draw a screen we do not wait until the next 100ms
time slot comes. We draw the next partial screen as fast as possible, but
give the system a chance to refill the buffers a bit.

When we see, during drawing a screen, the screen contend has changed,
we stop the current draw and begin to draw the new content from the top.

And reduce the function size to simplify

.. and give the hint to try lower values if possible.

Simply apply enabled settings instead of requiring users to edit
stepper_indirection.cpp

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

implemented G-Code M355 into Marlin

About Configuration.h:
・Fix the PR #4899 (ABL: Enable by type. Bilinear for all.)
Remove Duplicated contents

・Fix the PR #4305 (Custom boot screen feature improvement)
Revert from "during boot" to "during bootup" in all the example
Configuration.h

・Fix the PR #4207 (Clean up, simplify and generalize the Allen-key-probe
code.)
Resolve and relocate the duplicated definitions in Z_PROBE_ALLEN_KEY
section

・Follow-up the PR #4805 (Additional documentation of Configuration.h)
Add forgotten changes to all the example Configuration.h

Adjust spacing

About Configuration_adv.h:
Add missing description of SLOWDOWN for DELTA

Adjust spacing

Follow-up to #4666