Add references to FreeCam camera tilting keybinds

[metaclasscat]

Changes

• Added respective references to the key binds for the camera tilting feature, which can be accessed by the Z and C keys while actively inside of freecam.

Checks

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[github-actions]

Hi @sebastianlua, thanks so much for helping improve the Roblox creator documentation! Our technical writing team will review your pull request soon. In the meantime, please ensure you've read through the README.md, contribution guidelines, and style recommendations.