[doc] Improve Contribution Guidelines

[kvid]

I suggest adding some items in the Contribution Guidelines:

• Recommend creating a separate branch for each feature/bugfix that is pushed to your fork. (Unique branch name for each PR.)
• Recommend the advises from How to Write a Git Commit Message.
• If the dev branch has deviated from the PR branch before merge-time, recommend rebasing the PR branch on top of the new dev commits and resolve any conflicts before merge.
• If the PR branch contains branch merges or a high number of intermediate commits, recommend squashing some of them together using git rebase -i to simplify the commit history before merge.
• Maybe include the essential git commands?

[formatc1702]

I've added some of your points in the latest commit to #111.

Maybe include the essential git commands?

I'd rather not write a git tutorial... especially since I am not a CLI git user myself.
And interactive rebasing is an art unto itself.
If you have a good source, we can link to it, though!

[kvid]

I've added some of your points in the latest commit to #111.

Thank's

Maybe include the essential git commands?

I'd rather not write a git tutorial... especially since I am not a CLI git user myself.
And interactive rebasing is an art unto itself.
If you have a good source, we can link to it, though!

I've no such link suggestions at the moment