Make clipboard utility configurable

[fsackur]

Prerequisites

• Write a descriptive title.

Description of the new feature/enhancement

xclip is hard-coded in https://github.com/PowerShell/PSReadLine/blob/ff4bbd5ee/PSReadLine/Clipboard.cs#L80 and https://github.com/PowerShell/PSReadLine/blob/ff4bbd5ee/PSReadLine/Clipboard.cs#L117 .

Problems:

• xclip is not installed by default on Fedora 39
• If installed, xclip is likely to be the cause of Copy, CopyOrCancel and Cut commands hang in Linux until you copy in some other app #3884

Can we expose this as a PSReadLineOption?

Relevant: #1993 - PSReadLine has sucked for a long time at copy-paste on Linux 😥

Proposed technical implementation details (optional)

Any thoughts appreciated, but to get the ball rolling, I think we would likely need:

• CopyTool
• CopyToolArgs
• PasteTool
• PasteToolArgs

I suggest:

• A single object, to avoid adding 4 parameters:

  internal struct ClipboardTool
  {
      internal string Copy;
      internal string[] CopyArgs;
      internal string Paste;
      internal string[] PasteArgs;
  }

• Stipulate that CopyTool must accept input from the pipeline

• On Windows, setting the property throws an exception

• On Linux / Darwin you can do Set-PSReadlineOption -ClipboardTool @{Copy = 'xsel'; CopyArgs = ('-i', '--clipboard')}

  • Missing paste args, in this case, are init'd to xclip / pbcopy (the current defaults)

[daxian-dbw]

We don't plan to expose configuration about this, but we do need to fix the "hang" issue when using xclip.
Given that the fix #3937 was merged, I will close this one.