Add Clipboard to Clipboard Managers Section

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Types of Changes

What types of changes does your PR introduce?

• New addition to list
• Fixing bug in existing item in list
• Removing item from list
• Changing structure (organization) of list

Proposed Changes

This PR adds the "Clipboard" utility to the Clipboard Managers section where similar software is also located. However, unlike the other utilities, this one is entirely terminal-based, which makes it stand out from the others which all depend on the macOS GUI.

PR Checklist

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• I have added necessary documentation (if appropriate)

Further Comments

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