Update explanation comments

Author: user202729

src/sage/rings/integer.pyx

@@ -7556,8 +7556,8 @@ def _check_global_dummy_Integer():
         sage: _check_global_dummy_Integer()
         True
     """
-    # Check that it has exactly one limb allocated
-    # This is assumed later in fast_tp_new() :issue:`33081`
+    # Check that it has no allocation (requires GMP >= 6.2, see :issue:`31340`)
+    # fast_tp_new() later assumes that memcpy this mpz object gives a valid new mpz
     cdef mpz_ptr dummy = global_dummy_Integer.value
     if dummy._mp_alloc == 0 and dummy._mp_size == 0:
         return True
@@ -7648,7 +7648,7 @@ cdef PyObject* fast_tp_new(type t, args, kwds) except NULL:
     # The global_dummy_Integer may have a reference count larger than
     # one, but it is expected that newly created objects have a
     # reference count of one. This is potentially unneeded if
-    # everybody plays nice, because the gobal_dummy_Integer has only
+    # everybody plays nice, because the global_dummy_Integer has only
     # one reference in that case.
 
     # Objects from the pool have reference count zero, so this