Add buttons to copy code block contents

[kdkasad]

Adds a clickable "copy" link in the top-right corner of each code block.

If available, uses the navigator.clipboard API. Falls back to selecting
the text and calling document.execCommand('copy') to copy text.

I mainly focused on functionality, not style, so let me know if you want it to look different.

I tested on both Chrome and Firefox on Linux, and it works using both the navigator.clipboard API and the fallback method in both browsers.

Closes #344

[adityatelange]

@kdkasad Code looks good to me, works as expected !
Can you enable maintainer edits? so that I can change few styling stuff :)

[kdkasad]

@kdkasad Code looks good to me, works as expected !
Can you enable maintainer edits? so that I can change few styling stuff :)

Maintainer edits are now enabled.

Also I decided to add translation keys to support other languages.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[adityatelange]

@kdkasad I just noticed this doesn't work with

markup:
    highlight:
        lineNos: true

and code blocks not having a parent class highlight (ex. https://adityatelange.github.io/hugo-PaperMod/posts/markdown-syntax/)

[kdkasad]

@kdkasad I just noticed this doesn't work with

markup:
    highlight:
        lineNos: true

and code blocks not having a parent class highlight (ex. https://adityatelange.github.io/hugo-PaperMod/posts/markdown-syntax/)

It works fine with line numbers enabled for me. However you're right about it not working for non-highlight code blocks (i.e. ones indented with 4 spaces).

Edit: it also doesn't work for code blocks created using backticks with no syntax/language specified.

[adityatelange]

@kdkasad I just noticed this doesn't work with

markup:
    highlight:
        lineNos: true

and code blocks not having a parent class highlight (ex. https://adityatelange.github.io/hugo-PaperMod/posts/markdown-syntax/)

It works fine with line numbers enabled for me. However you're right about it not working for non-highlight code blocks (i.e. ones indented with 4 spaces).

Yes you are correct, it works fine with lineNos enabled. Maybe I should've restarted hugo's server.