Improve RST and MD files

CONTRIBUTING.md

@@ -3,29 +3,30 @@
 The SOPS project welcomes contributions from everyone. Here are a few guidelines
 and instructions if you are thinking of helping with the development of SOPS.
 
-# Getting started
+## Getting started
 
 - Make sure you have Go 1.19 or greater installed. You can find information on
   how to install Go [here](https://go.dev/doc/install)
 - Clone the Git repository and switch into SOPS's directory.
 - Run the tests with `make test`. They should all pass.
 - Fork the project on GitHub.
 - Add your fork to Git's remotes:
-  + If you use SSH authentication: `git remote add <your username> git@github.com:<your username>/sops.git`.
-  + Otherwise: `git remote add <your username> https://github.com/<your username>/sops.git`.
+   - If you use SSH authentication:
+     `git remote add <your username> git@github.com:<your username>/sops.git`.
+   - Otherwise: `git remote add <your username> https://github.com/<your username>/sops.git`.
 - Make any changes you want to SOPS, commit them, and push them to your fork.
 - **Create a pull request against `main`**, and a maintainer will come by and
   review your code. They may ask for some changes, and hopefully your
   contribution will be merged!
 
-# Guidelines
+## Guidelines
 
 - Unless it's particularly hard, changes that fix a bug should have a regression
   test to make sure that the bug is not introduced again.
 - New features and changes to existing features should be documented, and, if
   possible, tested.
 
-# Communication
+## Communication
 
 If you need any help contributing to SOPS, several maintainers are on the
 [`#sops-dev` channel](https://cloud-native.slack.com/archives/C059800AJBT) on