Refer to basic Github Fork+PR workflow in the docs

Is your feature request related to a problem? Please describe.

Every now and then, we can see that people who are new to git, GitHub, and open-source are facing difficulties with sending and updating a PRs while maintaining their local environment clean.

Describe the solution you'd like

I suggest adding a note \ tip \ important or a small section in the relevant locations of two of our contribution guides

• Contributing Code to Cutter
• Contributing Documentation to Cutter

An example to such paragraph can look something like this:

"Contributing to Cutter require you to have a basic knowledge of git and the Github Fork & Pull-Requst workflow. If you aren't familiar with the subjects, we highly recommend to read the "GitHub - Contributing to a Project" on the official and detailed Git Book."

I suggest to expand this example a little bit in the "Contributing Code to Cutter" page, and shortening it a bit in the "Contributing Documentation to Cutter" page

For the "Contributing Documentation to Cutter" it is also good to mention and link to how to edit files using the Edit (pencil icon) button. A useful link can be found on GitHub Documentation - Editing files.

Additional context

If you think that there are better tutorials, please suggest them :)