fix(guide): Add full solution code to jQuery challenges

[thecodingaviator]

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In addition to adding the full solution, the PR also removes the commented line saying Add code below here to maintain uniformity in this subsection of the guide

Refer #35271

[RandellDawson]

Tested all solutions and they work fine.

[RandellDawson]

Thank you for your contribution to the page! 👍
We're happy to accept these changes, and look forward to future contributions. 🎉