Stick REPL icon in quick action bar (#14064)

REPL Quick Actions

<img width="325" alt="image"
src="https://github.com/zed-industries/zed/assets/836375/faaf4c8f-ef12-4417-a9dd-158d5beae8ba">

When the Jupyter REPL is enabled and a kernel is available, show the
status in the editor bar:

![quick action bar
repl](https://github.com/zed-industries/zed/assets/836375/f3445283-f1fc-4714-895b-7aa842d4ab76)


Release Notes:

- N/A

---------

Co-authored-by: Nate Butler <iamnbutler@gmail.com>

crates/repl/src/session.rs

@@ -22,11 +22,11 @@ use theme::{ActiveTheme, ThemeSettings};
 use ui::{h_flex, prelude::*, v_flex, ButtonLike, ButtonStyle, Label};
 
 pub struct Session {
-    editor: WeakView<Editor>,
-    kernel: Kernel,
+    pub editor: WeakView<Editor>,
+    pub kernel: Kernel,
     blocks: HashMap<String, EditorBlock>,
-    messaging_task: Task<()>,
-    kernel_specification: KernelSpecification,
+    pub messaging_task: Task<()>,
+    pub kernel_specification: KernelSpecification,
 }
 
 struct EditorBlock {
@@ -310,7 +310,7 @@ impl Session {
         }
     }
 
-    fn interrupt(&mut self, cx: &mut ViewContext<Self>) {
+    pub fn interrupt(&mut self, cx: &mut ViewContext<Self>) {
         match &mut self.kernel {
             Kernel::RunningKernel(_kernel) => {
                 self.send(InterruptRequest {}.into(), cx).ok();
@@ -322,7 +322,7 @@ impl Session {
         }
     }
 
-    fn shutdown(&mut self, cx: &mut ViewContext<Self>) {
+    pub fn shutdown(&mut self, cx: &mut ViewContext<Self>) {
         let kernel = std::mem::replace(&mut self.kernel, Kernel::ShuttingDown);
 
         match kernel {