Actualize documentation

While original project, Profanity, provides valuable basis for this
fork, we are not affiliated with the upstream. Therefore, documentation
requires update reflecting accurate information.

The docs are going to be updated further once the website is created.

CONTRIBUTING.md

@@ -10,8 +10,8 @@ We recommend for people to always work on a dedicated git branch for each fix or
 Don't work on master.
 So that they can easily pull master and rebase their work if needed.
 
-For fixing (reported) bugs we usually use `git checkout -b fix/issuenumber-somedescription`.
-When working on a new feature we usually use `git checkout -b feature/optionalissuenumber-somedescription`.
+For fixing (reported) bugs we usually use `git switch -c fix/issuenumber-somedescription`.
+When working on a new feature we usually use `git switch -c feature/optionalissuenumber-somedescription`.
 
 However this is not a rule just a recommendation to keep an overview of things.
 If your change isn't a bugfix or new feature you can also just use any branch name.