Fix typo in Tempest Coding Guide.
"doctstrings" was mis-spelled as "docstings" in
tempest/HACKING.html
Change-Id: I0ae2b84af718cc032cd031612a898895a2b3c21d
Closes-bug: #1484356
diff --git a/HACKING.rst b/HACKING.rst
index 45c35df..6ddb8ac 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -275,7 +275,7 @@
Test Documentation
------------------
For tests being added we need to require inline documentation in the form of
-docstings to explain what is being tested. In API tests for a new API a class
+docstrings to explain what is being tested. In API tests for a new API a class
level docstring should be added to an API reference doc. If one doesn't exist
a TODO comment should be put indicating that the reference needs to be added.
For individual API test cases a method level docstring should be used to