time: Fix and better document time.struct_time constructor

INCOMPATIBLE CHANGE: struct_time(1,2,3,4,5,6,7,8,9) is now _rejected_
just as on standad Python.

This incorrect constructor was added by me in #2327; I assumed
without even checking that the `struct_time` constructor was also
compatible with the `namedtuple` constructor, but it is not and has
always been rejected by standard Python (checked 2.7 and 3.9)

This commit restores the specific error message that we used for this
purpose, which was removed in the previous commit either out of laziness
or out of trying to reduce unneeded error strings. In this case, the
alternate string is too misleading (it refers to arguments, not to
sequence elements) so let's put the better message back.

Author: jepler

shared-bindings/time/__init__.c

@@ -80,20 +80,21 @@ MP_DEFINE_CONST_FUN_OBJ_1(time_sleep_obj, time_sleep);
 
 #if MICROPY_PY_COLLECTIONS
 mp_obj_t struct_time_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
-    if (n_args != 1 || (kw_args != NULL && kw_args->used > 0)) {
-        return namedtuple_make_new(type, n_args, args, kw_args);
-    }
+    mp_arg_check_num(n_args, kw_args, 1, 1, false);
     size_t len;
     mp_obj_t *items;
     mp_obj_get_array(args[0], &len, &items);
+    if (len != 9) {
+        mp_raise_TypeError(translate("time.struct_time() takes a 9-sequence"));
+    }
     return namedtuple_make_new(type, len, items, NULL);
 }
 
 //| class struct_time:
-//|     def __init__(self, time_tuple: Tuple[int, int, int, int, int, int, int, int, int]) -> None:
-//|         """Structure used to capture a date and time. Note that it takes a tuple!
+//|     def __init__(self, time_tuple: Sequence) -> None:
+//|         """Structure used to capture a date and time.  Can be constructed from a `struct_time`, `tuple`, `list`, or `namedtuple` with 9 elements.
 //|
-//|         :param tuple time_tuple: Tuple of time info: ``(tm_year, tm_mon, tm_mday, tm_hour, tm_min, tm_sec, tm_wday, tm_yday, tm_isdst)``
+//|         :param Sequence time_tuple: Sequence of time info: ``(tm_year, tm_mon, tm_mday, tm_hour, tm_min, tm_sec, tm_wday, tm_yday, tm_isdst)``
 //|
 //|           * ``tm_year``: the year, 2017 for example
 //|           * ``tm_mon``: the month, range [1, 12]