Update blimp documentation to refer to Chrome

blimp/docs/markdown.md

 # How to use Markdown
 
 Markdown is a lightweight markup language which can be easily converted to
 HTML.
 
 ## Gitiles reference guide
 
 For the full reference guide for the version of Markdown used to render Chromium
 pages, see the [reference for Gitiles Markdown][gtref].
 
+## Google style guide
+
+Be sure to read the
+[Google style guide for Markdown](https://github.com/google/styleguide/blob/gh-pages/docguide/style.md).
+
 ## Local preview of changes
 
 To see how the pages you edit will look, run the following command from your
 Chromium checkout (`src/` directory) to start up a server on
 http://localhost:8080/:
 
 ```bash
 python tools/md_browser/md_browser.py
 ```
 
 You can then navigate to http://localhost:8080/blimp/README.md
 in your browser to see the result locally. Just refresh the page after saving
 a `*.md` file to see an updated result.
 
 [gtref]: https://gerrit.googlesource.com/gitiles/+/master/Documentation/markdown.md