fix flake8 ignore doc examples

this is because we have a missing display variable that gets injected

Author: rmorshea

setup.cfg

@@ -11,7 +11,7 @@ max-complexity = 18
 select = B,C,E,F,W,T4,B9,N
 exclude =
     idom/client/static/node_modules/*
-    docs/source/widgets/*
+    docs/source/examples/*
     .eggs/*
     .tox/*