🔧 More suppressible warnings (MarlinFirmware#27009)

* 🔧 Suppressible LCD contrast warning

* 🔧 Suppressible Z_SAFE_HOMING warning

* 🔧 Suppressible user feedback warning

Marlin/src/inc/Warnings.cpp

@@ -99,8 +99,8 @@
   #warning "Warning! Don't use dummy thermistors (998/999) for final build!"
 #endif
 
-#if NONE(HAS_RESUME_CONTINUE, HOST_PROMPT_SUPPORT, UNIT_TEST)
-  #warning "Your Configuration provides no method to acquire user feedback!"
+#if NONE(HAS_RESUME_CONTINUE, HOST_PROMPT_SUPPORT, UNIT_TEST, NO_USER_FEEDBACK_WARNING)
+  #warning "Your Configuration provides no method to acquire user feedback! (Define NO_USER_FEEDBACK_WARNING to suppress this warning.)"
 #endif
 
 #if MB(DUE3DOM_MINI) && PIN_EXISTS(TEMP_2) && !TEMP_SENSOR_BOARD
@@ -690,8 +690,8 @@
   #warning "To prevent step loss, motion will pause for PRINTCOUNTER auto-save."
 #endif
 
-#if HOMING_Z_WITH_PROBE && IS_CARTESIAN && DISABLED(Z_SAFE_HOMING)
-  #error "Z_SAFE_HOMING is recommended when homing with a probe. Enable Z_SAFE_HOMING or comment out this line to continue."
+#if HOMING_Z_WITH_PROBE && IS_CARTESIAN && NONE(Z_SAFE_HOMING, NO_Z_SAFE_HOMING_WARNING)
+  #error "Z_SAFE_HOMING is recommended when homing with a probe. (Enable Z_SAFE_HOMING or define NO_Z_SAFE_HOMING_WARNING to suppress this warning.)"
 #endif
 
 #if ENABLED(BIQU_MICROPROBE_V2) && NONE(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN, NO_MICROPROBE_WARNING)
@@ -718,8 +718,8 @@
   #warning "Disabled CONFIGURATION_EMBEDDING because the target usually has less flash storage. Define FORCE_CONFIG_EMBED to override."
 #endif
 
-#if HAS_LCD_CONTRAST && LCD_CONTRAST_MIN >= LCD_CONTRAST_MAX
-  #warning "Contrast cannot be changed when LCD_CONTRAST_MIN >= LCD_CONTRAST_MAX."
+#if HAS_LCD_CONTRAST && LCD_CONTRAST_MIN >= LCD_CONTRAST_MAX && DISABLED(NO_LCD_CONTRAST_WARNING)
+  #warning "Contrast cannot be changed when LCD_CONTRAST_MIN >= LCD_CONTRAST_MAX. (Define NO_LCD_CONTRAST_WARNING to suppress this warning.)"
 #endif
 
 #if PROGRESS_MSG_EXPIRE > 0 && HAS_STATUS_MESSAGE_TIMEOUT