typo : lower()->.lower() in Title, because all other documents have '…

[goldleo1]

Fixed a typo in content/lua/concepts/strings/terms/lower/lower.md by changing the title from "lower" to ".lower" to maintain consistency with other function names that include a leading dot (.).

Key changes:

• content/lua/concepts/strings/terms/lower/lower.md : fixed typo

IMPORTANT
This change is only a typo fix.

Description

• fixing typo

Issue Solved

Type of Change

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

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.