Feat: Enable always jumping to discussion tree

[jakubbortlik]

This PR makes it possible to customize the behavior when pressing the move_to_discussion_tree keybinding in the reviewer and there is no diagnostic under the cursor. Users can now set up any combination of:

• show warning
• jump to last position in discussion tree

Closes #309.

[jakubbortlik]

Hi @harrisoncramer, this PR changes the current behaviour - the new default is to always jump to the discussion tree even if there is no diagnostic under the cursor, as I believe this behaviour will be preferred by the majority of users. If, instead, you'd like the default to be that only a warning is shown (same as the old behaviour), I'll make the necessary changes.

[harrisoncramer]

This is a pretty simple feature, and I don't think it merits two new fields in the configuration table. I'd like to keep the API surface as small as possible for users.

Let's have it be a single option called jump_with_no_diagnostics and if it's enabled, do not show any warning and do the jump. Otherwise (it should be the. default case) do not jump and show the warning.

    if state.settings.reviewer_settings.jump_with_no_diagnostics then
      vim.api.nvim_win_set_cursor(M.split.winid, { M.last_row, M.last_column })
      vim.api.nvim_set_current_win(M.split.winid)
    else
      local warning = "No diagnostics for this line."
      u.notify(warning, vim.log.levels.WARN)
    end

[jakubbortlik]

OK, fixed. Thanks for the review.

[harrisoncramer]

Small change, but once you make that I'll merge this in. Sorry this took me so long to get to.