style: linting markdown files

Linting markdown files according to default remark-lint configuration.

Files inside the `public` directory were not linted.

Signed-off-by: oupala <oupala@users.noreply.github.com>

CONTRIBUTING.md

@@ -3,17 +3,22 @@
 When contributing to this repository, please first discuss the change you wish to make via issue,
 email, or any other method with the owners of this repository before making a change.
 
-Please note we have a [code of conduct](CODE_OF_CONDUCT.md), please follow it in all your
+Please note we have a [code of conduct](CODE-OF-CONDUCT.md), please follow it in all your
 interactions with the project.
 
 ## Pull Request Process
+
 1. Ensure you signed all your commits with Developer Certificate of Origin (DCO).
+
 2. Ensure any install or build dependencies are removed before the end of the layer when doing a
    build.
+
 3. Update the README.md with details of changes to the interface, this includes new environment
    variables, exposed ports, useful file locations and container parameters.
+
 4. Increase the version numbers in any examples files and the README.md to the new version that this
    Pull Request would represent. The versioning scheme we use is [SemVer](http://semver.org/).
+
 5. You may merge the Pull Request in once you have the sign-off of two other developers, or if you
    do not have permission to do that, you may request the second reviewer to merge it for you.
 
@@ -26,9 +31,9 @@ their contribution under the project's license.
 Please read [docs/legal/developer-certificate-of-origin.txt][dcofile].
 If you can certify it, then just add a line to every git commit message:
 
-````
+```git
   Signed-off-by: Random J Developer <random@developer.example.org>
-````
+```
 
 Use your real name (sorry, no pseudonyms or anonymous contributions).
 If you set your `user.name` and `user.email` git configs, you can sign your