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>

docs/src/SUMMARY.md

@@ -22,6 +22,7 @@
 - [Collaboration](./collaboration.md)
 - [Tasks](./tasks.md)
 - [Remote Development](./remote-development.md)
+- [Repl](./repl.md)
 
 # Language Support
 

docs/src/repl.md

@@ -0,0 +1,72 @@
+# REPL
+
+Read. Eval. Print. Loop.
+
+<div class="warning">
+
+This feature is in active development. Details may change. We're delighted to get feedback as the REPL feature evolves.
+
+</div>
+
+
+The built-in REPL for Zed allows you to run code interactively in your editor similarly to a notebook with your own text files.
+
+<!-- TODO: Include GIF in action -->
+
+To start using the REPL, add the following to your Zed `settings.json` to bring the power of [Jupyter kernels](https://docs.jupyter.org/en/latest/projects/kernels.html) to your editor:
+
+```json
+{
+  "jupyter": {
+    "enabled": true
+  }
+}
+```
+
+After that, install any of the supported kernels:
+
+* [Python](#python)
+* [TypeScript via Deno](#deno)
+
+## Python
+
+### Global environment
+
+To setup your current python to have an available kernel, run:
+
+```
+python -m ipykernel install --user
+```
+
+### Conda Environment
+
+```
+source activate myenv
+conda install ipykernel
+python -m ipykernel install --user --name myenv --display-name "Python (myenv)"
+```
+
+
+### Virtualenv with pip
+
+```
+source activate myenv
+pip install ipykernel
+python -m ipykernel install --user --name myenv --display-name "Python (myenv)"
+```
+
+## Deno
+
+[Install Deno](https://docs.deno.com/runtime/manual/getting_started/installation/) and then install the Deno jupyter kernel:
+
+```
+deno jupyter --unstable --install
+```
+
+## Other languages
+
+* [Julia](https://github.com/JuliaLang/IJulia.jl)
+* R
+  - [Ark Kernel from Positron, formerly RStudio](https://github.com/posit-dev/ark)
+  - [Xeus-R](https://github.com/jupyter-xeus/xeus-r)
+* [Scala](https://almond.sh/docs/quick-start-install)