title: How do I indicate that there are available code / hover actions in the sign column of NeoVim
body: <p>I am using <code>rust-tools</code> and everything is working fine with inlay hints, diagnostics etc. The code actions are also working fine in that when I call the dialog on a line I get the options and can apply them just fine. The only issue is that I don't know when a code action is available so I would like to add something in the sign column that indicates the presence of available hover actions.</p>