py/objtype: Make mp_obj_new_type a static function.

It's only used once, in the same file it's defined, and making it static
reduces code size.

Along with this, the associated example code comment in `ports/unix/main.c`
has been removed.

Signed-off-by: Damien George <damien@micropython.org>

Author: dpgeorge

ports/unix/main.c

@@ -616,19 +616,6 @@ MP_NOINLINE int main_(int argc, char **argv) {
     }
     #endif
 
-    // Here is some example code to create a class and instance of that class.
-    // First is the Python, then the C code.
-    //
-    // class TestClass:
-    //     pass
-    // test_obj = TestClass()
-    // test_obj.attr = 42
-    //
-    // mp_obj_t test_class_type, test_class_instance;
-    // test_class_type = mp_obj_new_type(qstr_from_str("TestClass"), mp_const_empty_tuple, mp_obj_new_dict(0));
-    // mp_store_name(qstr_from_str("test_obj"), test_class_instance = mp_call_function_0(test_class_type));
-    // mp_store_attr(test_class_instance, qstr_from_str("attr"), mp_obj_new_int(42));
-
     /*
     printf("bytes:\n");
     printf("    total %d\n", m_get_total_bytes_allocated());

py/obj.h

@@ -987,7 +987,6 @@ void *mp_obj_malloc_with_finaliser_helper(size_t num_bytes, const mp_obj_type_t
 bool mp_obj_is_dict_or_ordereddict(mp_obj_t o);
 #define mp_obj_is_fun(o) (mp_obj_is_obj(o) && (((mp_obj_base_t *)MP_OBJ_TO_PTR(o))->type->name == MP_QSTR_function))
 
-mp_obj_t mp_obj_new_type(qstr name, mp_obj_t bases_tuple, mp_obj_t locals_dict);
 static inline mp_obj_t mp_obj_new_bool(mp_int_t x) {
     return x ? mp_const_true : mp_const_false;
 }

py/objtype.c

@@ -44,6 +44,7 @@
 #define ENABLE_SPECIAL_ACCESSORS \
     (MICROPY_PY_DESCRIPTORS || MICROPY_PY_DELATTR_SETATTR || MICROPY_PY_BUILTINS_PROPERTY)
 
+static mp_obj_t mp_obj_new_type(qstr name, mp_obj_t bases_tuple, mp_obj_t locals_dict);
 static mp_obj_t mp_obj_is_subclass(mp_obj_t object, mp_obj_t classinfo);
 static mp_obj_t static_class_method_make_new(const mp_obj_type_t *self_in, size_t n_args, size_t n_kw, const mp_obj_t *args);
 
@@ -1164,7 +1165,7 @@ MP_DEFINE_CONST_OBJ_TYPE(
     attr, type_attr
     );
 
-mp_obj_t mp_obj_new_type(qstr name, mp_obj_t bases_tuple, mp_obj_t locals_dict) {
+static mp_obj_t mp_obj_new_type(qstr name, mp_obj_t bases_tuple, mp_obj_t locals_dict) {
     // Verify input objects have expected type
     if (!mp_obj_is_type(bases_tuple, &mp_type_tuple)) {
         mp_raise_TypeError(NULL);