Created activation functions in Pytorch

[arisdelacruz]

Description

This is an attempt to create an entry for the Activation functions in Pytorch.

Issue Solved

Closes #5231

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.