intermittent AT90USB & G26 compile problem (proposal)

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also an issue with ubl_motion.cpp

Add a sanity check for DELTA_AUTO_CALIBRATION

Fix LETTER_OFF in gcode.h (make LETTTER_OFF return values that match param indices range)

Correct has_value() when FASTER_GCODE_PARSER is enabled

Also corrected compile issue when DEBUG_GCODE_PARSER and
AUTO_BED_LEVELING_UBL are both enabled.

Add ANET A6 example configuration

Add A (action) and E (echo) parameters to M118

UBL Map Cleanup and LCD display

M118 echo to serial

Allows the user to send text to the serial console in order to
communicate with a host - sending debuging information or action
commands, for example.  Text must begin with '//' and this is added if
it is not already present at the beginning of the string.

Followups for I2C_POSITION_ENCODERS

Use parser.seenval, add shorthand functions

Initial support for the Průša MK2 Multiplexer

Followup to #6940

G33 F and Height bug fix

added missing italian translation

Fix #ifdef AVR_AT90USB1286_FAMILY in pinsDebug

Can't compile with PINS_DEBUGING enabled on Atmega1284p because it tries
to enumerate pins 46 and 47 (which don't exist) because `#ifdef
AVR_AT90USB1286_FAMILY ` doesn't work as expected.

Updated Czech language

Added option 'H' to G29 P4.

Fixup length

Fixes #7150

- Added `H` to set a nozzle height adjustment to surface of the bed.
- Updated G29 P4 comments to reflect changes.

Add Skynet/ANET A10 support