clean up contributing file headers

CONTRIBUTING.md

@@ -1,19 +1,15 @@
-.. highlight:: shell
+# Contributing
 
-============
-Contributing
-============
 
 Contributions are welcome, and they are greatly appreciated! Every little bit
 helps, and credit will always be given.
 
 You can contribute in many ways:
 
-Types of Contributions
-----------------------
+## Types of Contributions
+
+#### Report Bugs
 
-Report Bugs
-~~~~~~~~~~~
 
 Report bugs at https://github.com/gbouras13/dnaapler/issues.
 
@@ -23,27 +19,23 @@ If you are reporting a bug, please include:
 * Any details about your local setup that might be helpful in troubleshooting.
 * Detailed steps to reproduce the bug.
 
-Fix Bugs
-~~~~~~~~
+#### Fix Bugs
 
 Look through the GitHub issues for bugs. Anything tagged with "bug" and "help
 wanted" is open to whoever wants to implement it.
 
-Implement Features
-~~~~~~~~~~~~~~~~~~
+#### Implement Features
 
 Look through the GitHub issues for features. Anything tagged with "enhancement"
 and "help wanted" is open to whoever wants to implement it.
 
-Write Documentation
-~~~~~~~~~~~~~~~~~~~
+#### Write Documentation
 
 dnaapler could always use more documentation, whether as part of the
 official dnaapler docs, in docstrings, or even on the web in blog posts,
 articles, and such.
 
-Submit Feedback
-~~~~~~~~~~~~~~~
+#### Submit Feedback
 
 The best way to send feedback is to file an issue at https://github.com/gbouras13/dnaapler/issues.
 
@@ -54,8 +46,7 @@ If you are proposing a feature:
 * Remember that this is a volunteer-driven project, and that contributions
   are welcome :)
 
-Get Started!
-------------
+## Get Started!
 
 Ready to contribute? Here's how to set up `dnaapler` for local development.
 
@@ -93,8 +84,7 @@ Ready to contribute? Here's how to set up `dnaapler` for local development.
 
 7. Submit a pull request through the GitHub website.
 
-Pull Request Guidelines
------------------------
+## Pull Request Guidelines
 
 Before you submit a pull request, check that it meets these guidelines: