feat(gitbrowse): add copy_url to gitbrowse

[barnabasJ]

Description

Adds the copy_url function to gitbrowse to copy the url directly to the clipboard instead of opening it in the browser

[dpetka2001]

The open handler for opening urls is exposed in the settings already. You can just do

map({"n", "x" }, "<leader>gY", function()
  Snacks.gitbrowse({ open = function(url) vim.fn.setreg("+", url) end, notify = false })
end, { desc = "Git Browse (copy)" })

to implement this functionality which is a lot simpler.

[github-actions[bot]]

This PR is stale because it has been open 30 days with no activity.