[Edit] Fix typo in CSS Overflow entry

[joegorithm]

Description

• Edited the CSS Overflow concept file
• Added a missing colon (:) on line 19 of /content/css/concepts/overflow/overflow.md

It was previously this:

- `hidden` When set to this value, any content that overflows will be hidden from view.

And I changed it to this to match other list items:

- `hidden`: When set to this value, any content that overflows will be hidden from view.

Type of Change

• Editing an existing entry (fixing a typo, bug, issues, etc)

Checklist

• All writings are my own.
• My entry follows the Codecademy Docs style guide.
• My changes generate no new warnings.
• I have performed a self-review of my own writing and code.
• I have checked my entry and corrected any misspellings.
• I have made corresponding changes to the documentation if needed.
• I have confirmed my changes are not being pushed from my forked main branch.
• I have confirmed that I'm pushing from a new branch named after the changes I'm making.
• I have linked any issues that are relevant to this PR in the Issues Solved section.

[CLAassistant]

All committers have signed the CLA.

[mamtawardhani]

Thank you for contributing to Codecademy Docs @joegorithm 😄

The entry looks good for a second round of review! 🚀

[Radhika-okhade]

Thank you for contributing to Codecademy Docs @joegorithm 😄

The entry looks good to be merged. 🚀

[github-actions]

👋 @joegorithm
You have contributed to Codecademy Docs, and we would like to know more about you and your experience.
Please take a minute to fill out this four question survey to help us better understand Docs contributions and how we can improve the experience for you and our learners.
Thank you for your help!

🎉 Your contribution(s) can be seen here:

https://www.codecademy.com/resources/docs/css/overflow

Please note it may take a little while for changes to become visible.
If you're appearing as anonymous and want to be credited, visit the linked accounts page and ensure that your GitHub account is linked.