Just refer to the spec in PEP 484 for straddling annotations instead of repeating the info in PEP 8.

pep-0008.txt

@@ -1289,21 +1289,8 @@ annotations are changing.
   the library author's permission) through the typeshed repo [4]_.
 
 - For code that needs to be backwards compatible, function annotations
-  can be added in the form of comments.  Basically, this Python 3 annotation::
-
-    def embezzle(self, account: str, funds: int = 1000000, **fake_receipts: str) -> None:
-        """Embezzle funds from account using fake receipts."""
-        <code goes here>
-
-  is equivalent to the following::
-
-    def embezzle(self, account, funds=1000000, **fake_receipts):
-        # type: (str, int, **str) -> None
-        """Embezzle funds from account using fake receipts."""
-        <code goes here>
-
-  The mypy type checker [5]_ currently supports this syntax, and other
-  type checkers are encouraged to adopt it.
+  can be added in the form of comments.  See the relevant section of
+  PEP 484 [5]_.
 
 
 .. rubric:: Footnotes
@@ -1329,9 +1316,8 @@ References
 .. [4] Typeshed repo
    https://github.com/python/typeshed
 
-.. [5] mypy type checker
-   http://mypy-lang.org
-   https://github.com/JukkaL/mypy
+.. [5] Suggested syntax for Python 2.7 and straddling code
+   https://www.python.org/dev/peps/pep-0484/#suggested-syntax-for-python-2-7-and-straddling-code