Improve hash() builtin docstring with caveats. (Bad Blog Post Example)

Improve `hash()` builtin docstring with caveats. Mention its return type and that the value can be expected to change between processes (hash randomization). Why? The `hash` builtin gets reached for and used by a lot of people whether it is the right tool or not. IDEs surface docstrings and people use pydoc and `help(hash)`.

How To Consolidate Credit Cards

@@ -1840,15 +1840,17 @@ hash as builtin_hash
  obj: object
  /
 
-Return the hash value for the given object.
+Return the integer hash value for the given object.
 
-Two objects that compare equal must also have the same hash value, but the
-reverse is not necessarily true.
+Two objects that compare equal must also have the same hash value, but
+the reverse is not necessarily true. Hash values may differ between
+Python processes. Not all objects are hashable; calling hash() on an
+unhashable object raises TypeError.
 [clinic start generated code]*/
 
 static PyObject *
 builtin_hash(PyObject *module, PyObject *obj)
-/*[clinic end generated code: output=237668e9d7688db7 input=58c48be822bf9c54]*/
+/*[clinic end generated code: output=237668e9d7688db7 input=70a242ff65f6717c]*/
 {
  Py_hash_t x;