Because the *working with git* section is quite long, it obscures the
*writing documentation* section. Move it to before the *working with
git* section.
Having two lists that need to be read thouroughly for pull requests is
unclear. Clean this up by:
- Splitting the *pull request* steps into *coding conventions*,
*commit conventions*, and *pull requests*
- Completing the contribution steps with references to those sections.
- Reordering all steps to any contributor will encounter them in order.
- Rename and promote 'Git usage', to a 'Working with Git' section.
This is then referred to at the start of the document and in
the contribution steps.
The naming of the 'help wanted' section is unclear, and unhelpful.
Additionally, most of the items listed in it are not actually part of
the contribution process:
- While *Documentation* is welcome, it is not helpful to document the
kinds in the contributing document. The contributing document should
document *how*, not *what*.
- The *Issues* section is out of place: I doubt anyone will look at the
*contributing guidelines* to find out how to open an issue.
The content is also pretty self-explanatory.
- What's left is only 'Contributing Code', so promote it!
Updated the link to the coding conventions in CONTRIBUTING.md and MAINTAINING.md
to no longer point to the wiki, but to CODING_CONVENTIONS.md in the RIOT
repository.
