feat: Add term entry for React useMemo() hook #8259

[pswitchy]

Description

Added a new term entry for the useMemo() React Hook. The entry is located at [docs/content/react/concepts/hooks/terms/useMemo/useMemo.md] and includes:

• An introduction explaining what useMemo() does and why it is useful
• A Syntax section with usage details and parameter explanations
• An Example section demonstrating memoized filtering with a practical component

Issue Solved

Closes #8259

Type of Change

• Adding a new entry

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]

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