Fix typo: Add period before Abs() in title (fixes #7972)

[pramod5403]

Description

Added a period (.) before Abs() in the title to match the naming convention used in other entries in the math-functions directory.

Issue Solved

Closes #7972

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]

We already have a PR for this, so closing this one.