[NEW] Update CONTRIBUTING.md and improve developer experience around clang-format

[PingXie]

We could also add a make target like make format that just formats the code appropriately, which can be run if CI fails or before committing.

Originally posted by @bjosv in #538 (comment)

[hahnandrew]

Here's a quick PR

which can be run before committing.

Was unsure here if you were referring to an automated process like hooks that run on the staged files so no one manually runs make format. Happy to add it to the PR - let me know what you think @PingXie

[PingXie]

git clang-format is a good alternative as well (and has been working well for me). @bjosv, what do you think?

[hahnandrew]

We should definitely stick to what works, I'll close out the PR in favor of git clang-format

[bjosv]

git clang-format is a good alternative as well (and has been working well for me). @bjosv, what do you think?

Oh, never seen it, but it looks neat!