Add new Button and IconButton components (#3448)

This PR adds new `Button` and `IconButton` components built on top of
our new button abstractions.

Both of these buttons are built from the common `ButtonLike` base, and
implement the `ButtonCommon` (name TBD) trait in order to provide a
common interface.

There are still some visual tweaks that we'll need to make to the new
buttons, but those should be straightforward to make after we land this.

Release Notes:

- N/A

crates/workspace2/src/notifications.rs

@@ -181,6 +181,7 @@ pub mod simple_message_notification {
     };
     use serde::Deserialize;
     use std::{borrow::Cow, sync::Arc};
+    use ui::prelude::*;
     use ui::{h_stack, v_stack, Button, Icon, IconElement, Label, StyledExt};
 
     #[derive(Clone, Default, Deserialize, PartialEq)]
@@ -287,12 +288,14 @@ pub mod simple_message_notification {
                         ),
                 )
                 .children(self.click_message.iter().map(|message| {
-                    Button::new(message.clone()).on_click(cx.listener(|this, _, cx| {
-                        if let Some(on_click) = this.on_click.as_ref() {
-                            (on_click)(cx)
-                        };
-                        this.dismiss(cx)
-                    }))
+                    Button::new(message.clone(), message.clone()).on_click(cx.listener(
+                        |this, _, cx| {
+                            if let Some(on_click) = this.on_click.as_ref() {
+                                (on_click)(cx)
+                            };
+                            this.dismiss(cx)
+                        },
+                    ))
                 }))
         }
     }

crates/workspace2/src/status_bar.rs

@@ -71,14 +71,14 @@ impl Render for StatusBar {
                                 div()
                                     .border()
                                     .border_color(gpui::red())
-                                    .child(Button::new("15:22")),
+                                    .child(Button::new("status_line_column_numbers", "15:22")),
                             )
                             .child(
                                 // TODO: Language picker
                                 div()
                                     .border()
                                     .border_color(gpui::red())
-                                    .child(Button::new("Rust")),
+                                    .child(Button::new("status_buffer_language", "Rust")),
                             ),
                     )
                     .child(

crates/workspace2/src/toolbar.rs

@@ -94,9 +94,9 @@ impl Render for Toolbar {
                             .border()
                             .border_color(gpui::red())
                             .p_1()
-                            .child(Button::new("crates"))
+                            .child(Button::new("breadcrumb_crates", "crates"))
                             .child(Label::new("/").color(Color::Muted))
-                            .child(Button::new("workspace2")),
+                            .child(Button::new("breadcrumb_workspace2", "workspace2")),
                     )
                     // Toolbar right side
                     .child(