🔨🐛 Don't use broken 'board = fysetc_f6_13' (#28159)

Marlin/src/pins/pins.h

@@ -178,9 +178,9 @@
 #elif MB(DAGOMA_F5)
   #include "ramps/pins_DAGOMA_F5.h"                 // ATmega2560                           env:mega2560
 #elif MB(FYSETC_F6_13)
-  #include "ramps/pins_FYSETC_F6_13.h"              // ATmega2560                           env:FYSETC_F6
+  #include "ramps/pins_FYSETC_F6_13.h"              // ATmega2560                           env:mega2560ext
 #elif MB(FYSETC_F6_14)
-  #include "ramps/pins_FYSETC_F6_14.h"              // ATmega2560                           env:FYSETC_F6
+  #include "ramps/pins_FYSETC_F6_14.h"              // ATmega2560                           env:mega2560ext
 #elif MB(DUPLICATOR_I3_PLUS)
   #include "ramps/pins_DUPLICATOR_I3_PLUS.h"        // ATmega2560                           env:mega2560
 #elif MB(VORON)

buildroot/tests/mega2560ext

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 #
-# Build tests for AVR ATmega FYSETC F6 1.3
+# Build tests for mega2560ext - AVR ATmega (extended)
 #
 
 # exit on first failure
@@ -64,7 +64,7 @@ opt_set MOTHERBOARD BOARD_FYSETC_F6_13 \
 opt_enable USE_ZMIN_PLUG FIX_MOUNTED_PROBE AUTO_BED_LEVELING_BILINEAR PAUSE_BEFORE_DEPLOY_STOW \
            FYSETC_242_OLED_12864 EEPROM_SETTINGS EEPROM_CHITCHAT M114_DETAIL Z_SAFE_HOMING \
            STEALTHCHOP_XY STEALTHCHOP_Z STEALTHCHOP_E HYBRID_THRESHOLD SENSORLESS_HOMING SQUARE_WAVE_STEPPING
-exec_test $1 $2 "FYSETC_F6 | SCARA | Mixed TMC | EEPROM" "$3"
+exec_test $1 $2 "SCARA | Mixed TMC | EEPROM" "$3"
 
 # clean up
 restore_configs

ini/avr.ini

@@ -87,13 +87,6 @@ board    = megaatmega2560
 extends  = common_avr8
 board    = reprap_rambo
 
-#
-# FYSETC F6 V1.3 / V1.4
-#
-[env:FYSETC_F6]
-extends  = common_avr8
-board    = fysetc_f6_13
-
 #
 # Sanguinololu (ATmega644p)
 #

ini/renamed.ini

@@ -95,3 +95,6 @@ extends = renamed
 
 [env:STM32F407ZE_btt_USB]             ;=> STM32F407ZE_btt_usb_flash_drive
 extends = renamed
+
+[env:FYSETC_F6]                       ;=> mega2560ext
+extends = renamed