New revision of the Assistant Panel (#10870)

This is a crate only addition of a new version of the AssistantPanel.
We'll be putting this behind a feature flag while we iron out the new
experience.

Release Notes:

- N/A

---------

Co-authored-by: Nathan Sobo <nathan@zed.dev>
Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Conrad Irwin <conrad@zed.dev>
Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>
Co-authored-by: Antonio Scandurra <antonio@zed.dev>
Co-authored-by: Nate Butler <nate@zed.dev>
Co-authored-by: Nate Butler <iamnbutler@gmail.com>
Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>
Co-authored-by: Max <max@zed.dev>

crates/ui/src/components/tooltip.rs

@@ -95,7 +95,7 @@ pub fn tooltip_container<V>(
     div().pl_2().pt_2p5().child(
         v_flex()
             .elevation_2(cx)
-            .font(ui_font)
+            .font_family(ui_font)
             .text_ui()
             .text_color(cx.theme().colors().text)
             .py_1()