DOC: Website should copy code only

[DoNguyenHung]

• closes DOC: Website should copy code only #56388
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

Changes made:

• Added sphinx-toggleprompt
• Removed Python REPL prompts from code after using the copy button in code cells
• I'm aware that the preferable solution is to sphinx-toggleprompt so users have the choice whether to copy the prompt or not (from add sphinx-copybutton configurations to exclude prompts #59370). However, this toggle is implemented using copybutton, particularly <span class="copybutton" data-hidden="true"> elements (see documentation here). These spans represent the prompt text and are styled with display: none when hidden. However, they share the same copybutton class name as the actual copybutton UI <button class="copybtn">, which introduces ambiguity in the DOM structure. On top of that, when the copy button is clicked, sphinx-copybutton copies the full text content of the target code block. It does not inspect data-hidden="true" or CSS visibility, and it does not differentiate between visible and hidden prompt spans. As a result, REPL prompts are included in the copied output even when they are visually hidden.
• I tried to override this behavior using custom JavaScript (see my previous commits), but I was unsuccessful because:
  • copybutton and toggleprompt both share the same copybutton class, making it difficult to isolate prompt content from UI elements.
  • The toggle state is not exposed in a way that allows reliable filtering during the copy event.
  • The clipboard API copies raw text content and does not respect DOM visibility or custom attributes like data-hidden (mentioned above).
• Because of these limitations, I only made changes so that REPL prompts are always stripped from copied output using sphinx-copybutton's built-in prompt removal feature. The toggle remains available for visual clarity, but does not change the copy behavior. If anyone wants to copy the prompt, the best I can recommend is just use toggle and CTRL C + V.

[DoNguyenHung]

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