New messages translated:
#define MSG_LEVEL_BED_HOMING "Homing XYZ"
#define MSG_LEVEL_BED_WAITING "Click to Begin"
#define MSG_LEVEL_BED_DONE "Leveling Done!"
#define MSG_LEVEL_BED_CANCEL "Cancel"
. . .
#define MSG_HOME_OFFSETS_APPLIED "Offsets applied"

Comments for legibility, include DEBUG_LEVELING, SDSUPPORT

Fix: menu edit items saving position twice

Drop DISABLE_M(IN|AX)_ENDSTOPS, replace with individual endstop flags

Added a script to check all language files for missing translations

Add Missing Spanish translation

Update language_nl.h

Add the missing translation (Spanish) issue #3353

Added these messages with Dutch translation
#define MSG_BED_Z
#define MSG_A_TRAVEL
#define MSG_HEATING_FAILED_LCD
#define MSG_ERR_REDUNDANT_TEMP
#define MSG_THERMAL_RUNAWAY
#define MSG_ERR_MAXTEMP
#define MSG_ERR_MINTEMP
#define MSG_ERR_MAXTEMP_BED
#define MSG_ERR_MINTEMP_BED
#define MSG_HEATING
#define MSG_HEATING_COMPLETE
#define MSG_BED_HEATING
#define MSG_BED_DONE

French translation

Update language_cz.h

Update language_it.h

M111: Add static keyword to PROGMEM debug variables

ADD missing translation

This is follow-up the commit e5771346a4.
Update unnoticed files.

Added missing translations for pt_PT

Fix bug in new endstop pullups handling

Fix M111 output using pgm_read_word, as required

Update Japanese translation

As noted by @taratata2016 in https://github.com/MarlinFirmware/Marlin/issues/3300#issuecomment-204687275

Simplified endstop configuration

suppress warnings

Fix English definition for MSG_LEVEL_BED_CANCEL

Update Japanese translation