feat: Add alt optional copy HTML to clipboard on demo site

[R055A]

Description

Add alternative option for copying HTML to the clipboard on the demo site.

Fixes #572

Type of change

• New feature (added a non-breaking change which adds functionality)

How Has This Been Tested?

• Tested locally with a valid username
• Tested locally with an invalid username
• Ran tests with composer test
• Added or updated test cases to test new features

Checklist:

• I have checked to make sure no other pull requests are open for this issue
• The code is properly formatted and is consistent with the existing code style
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

Screenshots

Haven't included images for entering a valid username, but can verify both Copy to Clipboard buttons enable

[DenverCoder1]

Looks great, I just have a minor suggestion.

Another thing to consider is maybe making a JSON Endpoint section appear when the type is set to JSON instead of having HTML and Markdown, but that can be saved for another PR if you prefer.

[R055A]

Looks great, I just have a minor suggestion.

Another thing to consider is maybe making a JSON Endpoint section appear when the type is set to JSON instead of having HTML and Markdown, but that can be saved for another PR if you prefer.

It may be better to make a new PR for the JSON clipboard feature. If you assign me to a new Issue for the JSON clipboard I can make a PR for it by today or tomorrow (depending time zone).

[DenverCoder1]

Looks great! Thanks for the contribution 🎉