PEP 827: update state of mypy proof-of-concept (#4869)

Author: msullivan

peps/pep-0827.rst

@@ -1458,11 +1458,7 @@ also where this PEP draft currently lives.
 
 There is an in-progress `proof-of-concept implementation <#ref-impl_>`__ in mypy.
 
-It can type check the ORM, FastAPI-style model derivation, and
-NumPy-style broadcasting examples.
-
-It is missing support for callables, ``UpdateClass``, annotation
-processing, and various smaller things.
+It can type check all of the examples in this document.
 
 Alternate syntax ideas
 ======================