Changed {:copy} function to remove any preceding $ before copying to clipboard

[jo-tree]

Why:

Closes #21645

What's being changed (if available, include any code snippets, screenshots, or gifs):

I have changed the function that copies the string to the clipboard when {:copy} is used in an .md file. The change will remove, if it is present, the preceding $

Check off the following:

• [ ] I have reviewed my changes in staging (look for the "Automatically generated comment" and click the links in the "Preview" column to view your latest changes).
• [x] For content changes, I have completed the self-review checklist.

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[cmwilson21]

@jo-tree Thank you for opening a PR and linking it to your issue! ✨

I'll get this triaged for review! ⚡

[cmwilson21]

👋 @jo-tree - Please see comment here and feel free to adjust this PR to reflect the request.

Thank you for your interest in improving the docs! 💖

[rachmari]

@jo-tree thanks for opening this up. There was some work to fix this internally already in motion, so I'm checking in with those folks to see if we want to make this change.

[cmwilson21]

👋 @jo-tree - We are discussing possible improvements in the copy button internally, so I'm going to go ahead and close this issue now 💛

Thank you for opening the issue and inspiring the internal talks! ✨