Fix up issue with PROGMEM and hand_swap_config

[zvecr]

Description

Currently spitting out error...

Compiling: keyboards/moonlander/matrix.c                                                           In file included from quantum/keymap.h:22,
                 from quantum/quantum.h:21,
                 from keyboards/moonlander/moonlander.h:23,
                 from keyboards/moonlander/matrix.c:19:
quantum/action.h:75:31: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'hand_swap_config'
   75 | extern const keypos_t PROGMEM hand_swap_config[MATRIX_ROWS][MATRIX_COLS];
      |                               ^~~~~~~~~~~~~~~~
 [ERRORS]
 | 
 | 
 | 
make[1]: *** [tmk_core/rules.mk:457: .build/obj_moonlander_default/matrix.o] Error 1

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).