Grammar tweak

it33 · web-flow · commit 09fd10ef6b8e · 2016-11-27T19:43:38.000-08:00
diff --git a/source/developer/fx-guidelines.rst b/source/developer/fx-guidelines.rst
@@ -418,7 +418,7 @@ Error message should not:
 - Say or have the term “Error”.
 - Be lengthy.
 - Be generic.
-- Avoid ending in exclaimation point.
+- End in an exclaimation point.
 
 **Examples:**
 
