fix(docs): add example for pageContext usage within a page

[guayom]

Description

This page explains very well that you can pass context to a page automatically created, but it's missing an example of how to use it in a page via pageContext. I think it is important to explicitly explain it because the name of the variable is different to the prop name.
I added an example.

Related Issues

I didn't find any related issues.

[guayom]

Oops, missed the jsx... Do I need to squash?

[DSchau]

@guayom no need! If you're able, can you fix the linter? In the root of your repo, should be

npx prettier --write docs/docs/creating-and-modifying-pages.md

[guayom]

:S Sorry, I didn't understand that part. Should I modify a file or run that command?

[DSchau]

Fixed it for you! Thanks for the PR 🎉

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[guayom]

Oh! Gotcha! I did the change from the UI, but now I see that the next time it's best to download the repo and run the linter before commiting. Thanks for your help and for working on this amazing software!

[DSchau]

Now you helped too :) Thanks for your help, we appreciate it!