Display available stories in storybook CLI (#3021)

This PR updates the storybook CLI to support displaying all of the
available stories.

The `--help` flag will now show a list of all the available stories:

<img width="1435" alt="Screenshot 2023-09-22 at 6 11 00 PM"
src="https://github.com/zed-industries/zed/assets/1486634/284e1a24-46ec-462e-9709-0f9b6e94931f">

Inputting an invalid story name will also show the list of available
stories:

<img width="1435" alt="Screenshot 2023-09-22 at 6 10 43 PM"
src="https://github.com/zed-industries/zed/assets/1486634/1ce3ae3f-ab03-4976-a06a-5a2b5f61eae3">

Release Notes:

- N/A

crates/storybook/Cargo.toml

@@ -10,7 +10,7 @@ path = "src/storybook.rs"
 
 [dependencies]
 anyhow.workspace = true
-clap = { version = "3.1", features = ["derive"] }
+clap = { version = "4.4", features = ["derive", "string"] }
 gpui2 = { path = "../gpui2" }
 log.workspace = true
 rust-embed.workspace = true