stm32/mpconfigport.h: Enable MICROPY_PY_REVERSE_SPECIAL_METHODS.
It's a useful core feature.
#define MICROPY_PY_BUILTINS_SLICE_INDICES (1)
#define MICROPY_PY_BUILTINS_ROUND_INT (1)
#define MICROPY_PY_ALL_SPECIAL_METHODS (1)
+#define MICROPY_PY_REVERSE_SPECIAL_METHODS (1)
#define MICROPY_PY_BUILTINS_COMPILE (MICROPY_ENABLE_COMPILER)
#define MICROPY_PY_BUILTINS_EXECFILE (MICROPY_ENABLE_COMPILER)
#define MICROPY_PY_BUILTINS_NOTIMPLEMENTED (1)
