DOC: Update beginners docu for sum function with axis

[EvaJau]

Hopefully clarifies how summing over an axis is done. Fixes #16697

[melissawm]

Hi @EvaJau - you can edit your description to say either "Closes #16697", "Fixes #16697" or any of the other magic words listed here: https://docs.github.com/pt/github/managing-your-work-on-github/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword

[EvaJau]

Hi @EvaJau - you can edit your description to say either "Closes #16697", "Fixes #16697" or any of the other magic words listed here: https://docs.github.com/pt/github/managing-your-work-on-github/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword

Yes, sure. Thanks for the hint!

[melissawm]

Hi @EvaJau just in case you were pairing up with someone to work on this, do you want to add them as co-author to your commit message?

[EvaJau]

Hi @EvaJau just in case you were pairing up with someone to work on this, do you want to add them as co-author to your commit message?

Hey, I didn't pair for this issue but thanks for asking!

[melissawm]

This looks good to me, although I'm not a native English speaker it does look clearer. Thanks!