What happened?
Invoking the "editor: show signature help" command does nothing.
What did you expect to happen?
A pop-up showing the signature of the method should appear. Here's an example from using it in a Dart file:

I feel like this has worked in an earlier version, but might be mistaken.
Environment
Zed: v0.224.10+stable.172.b1ff85bfd51ab530fd5774929efabfc5b2b4043c (Zed)
OS: Windows 10.0.26200
Java extension: v6.8.10