py: Annotate func defs with NORETURN when their corresp decls have it.

py/objstr.c

@@ -2084,7 +2084,7 @@ bool mp_obj_str_equal(mp_obj_t s1, mp_obj_t s2) {
     }
 }
 
-STATIC void bad_implicit_conversion(mp_obj_t self_in) {
+STATIC NORETURN void bad_implicit_conversion(mp_obj_t self_in) {
     if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
         mp_raise_TypeError("can't convert to str implicitly");
     } else {

py/stackctrl.c

@@ -48,7 +48,7 @@ void mp_stack_set_limit(mp_uint_t limit) {
     MP_STATE_THREAD(stack_limit) = limit;
 }
 
-void mp_exc_recursion_depth(void) {
+NORETURN void mp_exc_recursion_depth(void) {
     nlr_raise(mp_obj_new_exception_arg1(&mp_type_RuntimeError,
         MP_OBJ_NEW_QSTR(MP_QSTR_maximum_space_recursion_space_depth_space_exceeded)));
 }