Add function to fetch runnable at cursor position

[ERoydev]

Expose a command in the extension that provides an interface for fetching a specific Runnable from the LSP. This lets the user select a Runnable directly instead of using the debug command, which currently prompts them to choose between multiple runnables. The fetched Runnable can then be used to call the debugSingle command directly.

Open to suggestions if there’s existing functionality that already provides this.

Here’s an example of the behavior I’m trying to address::

[ERoydev]

can you suggest a solution ?

[rustbot]

:warning: Warning :warning:

• The following commits have merge commits (commits with multiple parents) in your changes. We have a no merge policy so these commits will need to be removed for this pull request to be merged.

  • 1c3fbc6e38f013ce7bece2d0a48582974cedab8f

  You can start a rebase with the following commands:

  $ # rebase
  $ git pull --rebase https://github.com/rust-lang/rust-analyzer.git master
  $ git push --force-with-lease