Make "hashable" a glossary entry and clarify docs on __cmp__, __eq__ and __hash__.
I hope the concept of hashability is better understandable now.
Thanks to Tim Hatch for pointing out the flaws here.
diff --git a/Doc/c-api/concrete.rst b/Doc/c-api/concrete.rst
index 209f3e6..a02332a 100644
--- a/Doc/c-api/concrete.rst
+++ b/Doc/c-api/concrete.rst
@@ -2231,8 +2231,8 @@
.. cfunction:: int PyDict_SetItem(PyObject *p, PyObject *key, PyObject *val)
Insert *value* into the dictionary *p* with a key of *key*. *key* must be
- hashable; if it isn't, :exc:`TypeError` will be raised. Return ``0`` on success
- or ``-1`` on failure.
+ :term:`hashable`; if it isn't, :exc:`TypeError` will be raised. Return ``0``
+ on success or ``-1`` on failure.
.. cfunction:: int PyDict_SetItemString(PyObject *p, const char *key, PyObject *val)