Add Copy-to-Clipboard Button for Code Blocks

[shekhar-narayan-mishra]

Problem

The documentation at https://docs.deno.com currently lacks a copy-to-clipboard button on code blocks. Users must manually select and copy command-line examples, which is inefficient and error-prone—especially for long commands or multiline examples.

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Proposed Solution

Add a visible copy button to each <pre><code> block that:

• Appears on the top-right corner (pinned)
• Copies raw text (excluding shell prompts like $, ❯, %, etc.)
• Shows a visual confirmation (checkmark) when copied
• Remains pinned even when the code is horizontally scrollable (like GitHub or ChatGPT)

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Why It Matters

This significantly improves user experience, particularly for beginners referencing install or setup commands. Most modern documentation systems already support this feature (e.g. GitHub, Vercel, Next.js, ChatGPT).

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Screenshots

Before:

After:

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Working Implementation

I have already implemented a working prototype in my fork:
🔗 https://github.com/shekhar-narayan-mishra/docs/tree/feat/docs-copy-button

I will raise a pull request referencing this issue shortly.