DOCS: indicate order of option items in commit message

[reshamas]

The current instructions are not clear on how -s should be included in commit message. This works:
git commit -m "message" -s

file: https://github.com/modin-project/modin/blob/master/docs/CONTRIBUTING.rst

[mvashishtha]

I think the current instructions are clear enough: https://modin.readthedocs.io/en/0.15.3/development/contributing.html#certificate-of-origin-v-1-1

[reshamas]

I think the current instructions are clear enough: https://modin.readthedocs.io/en/0.15.3/development/contributing.html#certificate-of-origin-v-1-1

If you say so. :)

[mvashishtha]

@reshamas thank you for responding to this issue even though it's so old!

It's a little hard to figure out what the contributing instructions said at the time you reported this issue, because the file has moved around since then. I assumed that there were no instructions about signing commits then. How could we make the current documentation clearer? I assume that readers know that command line flags for commands like git commit can appear in any order. Is that a bad assumption?

[reshamas]

I believe this issue was inspired by a challenge at an online sprint at PyData Global 2021 with @devin-petersohn.

Maybe the best way to see if the instructions are clear is to check again at a sprint or with new contributors. I haven't contributed to modin since last October.