Add copyright to clipboard when user copy

[Angboo]

PR Checklist

• The commit message follows guidelines for NexT.
• Tests for the changes was maked (for bug fixes / features).
  • Muse | Mist have been tested.
  • Pisces | Gemini have been tested.
• Docs in NexT website have been added / updated (for features).

PR Type

• Bugfix.
• Feature.
• Code style update (formatting, local variables).
• Refactoring (no functional changes, no api changes).
• Build related changes.
• CI related changes.
• Documentation content changes.
• Other... Please describe:

What is the current behavior?

Issue resolved: N/A

What is the new behavior?

• Screenshots with this changes: N/A
• Link to demo site with this changes: N/A

How to use?

In NexT _config.yml:

Does this PR introduce a breaking change?

• Yes.
• No.

[welcome]

Thanks so much for opening your first PR here!

[claassistantio]

All committers have signed the CLA.

[stevenjoezhang]

Thanks for your contributing!

However, this feature is not always user-friendly. Please make it a NexT plugin and submit a Pull Request here: https://github.com/next-theme/awesome-next#next-plugins

[Angboo]

@stevenjoezhang �I think this should be turned on when "creative_commons" is in use, so it should not be a plugins

[stevenjoezhang]

Thank you for your suggestions, but this does affect the reading experience. In fact, the use of creative commons is good enough now, it's a moral issue, not a technical one. As a Hexo theme, we must consider both bloggers and readers. Maybe there will be a better solution in the future.

[Angboo]

@stevenjoezhang Sorry, I ignore that, And I will create a plugin for next-theme

[stevenjoezhang]

Looking forward to your pull request 🎉

https://github.com/next-theme/awesome-next