fix(docs): move subheaders down a level for correct nav

The "PR Checklist" doc had all its subheaders at the same level as
the main header (h1 instead of h2), causing them to show up in the
right column navigation links.

Author: mboersma

docs/contributing/index.rst

@@ -1,5 +1,5 @@
 :title: Contributing
-:description: TOOD
+:description: How to contribute to the Deis open source PaaS project
 
 Contributing
 ============

docs/contributing/standards.rst

@@ -19,7 +19,7 @@ Please make sure your PR follows this checklist:
 
 
 Single Issue
-============
+------------
 
 When fixing or implementing a GitHub issue, resist the temptation to refactor
 nearby code or to fix that potential bug you noticed. Instead, open a new
@@ -39,7 +39,7 @@ will then be closed when your PR is merged.
 
 
 Include Tests
-=============
+-------------
 
 While working on local code changes, run Deis' tests:
 
@@ -68,7 +68,7 @@ See ``tests/README.md`` in the code for more information.
 
 
 Include Docs
-============
+------------
 
 Any change to Deis that could affect a user's experience also needs a change or
 addition to the relevant documentation. Deis generates the HTML documentation
@@ -79,7 +79,7 @@ See ``docs/README.md`` in the code for more information.
 
 
 Code Standards
-==============
+--------------
 
 Deis is a Go_ and Python_ project. For both languages, we agree with
 `The Zen of Python`_, which emphasizes simple over clever. Readability counts.
@@ -99,7 +99,7 @@ Deis does not enforce this.
 .. _commit_style_guide:
 
 Commit Style
-============
+------------
 
 ``git commit`` messages must follow this format::
 
@@ -164,7 +164,7 @@ for manual testing.
 
 
 Merge Approval
-==============
+--------------
 
 Deis maintainers add "**LGTM**" (Looks Good To Me) or an equivalent comment
 to indicate that a PR is acceptable. Any code change--other than