ruff server: Introduce the ruff.printDebugInformation command (#11831)

## Summary

Closes #11715.

Introduces a new command, `ruff.printDebugInformation`. This will print
useful information about the status of the server to `stderr`.

Right now, the information shown by this command includes:
* The path to the server executable
* The version of the executable
* The text encoding being used
* The number of open documents and workspaces
* A list of registered configuration files
* The capabilities of the client

## Test Plan

First, checkout and use [the corresponding `ruff-vscode`
PR](https://github.com/astral-sh/ruff-vscode/pull/495).

Running the `Print debug information` command in VS Code should show
something like the following in the Output channel:

<img width="991" alt="Screenshot 2024-06-11 at 11 41 46 AM"
src="ab93c009-bb7b-4291-b057-d44fdc6f9f86">

crates/ruff_server/src/session/capabilities.rs

@@ -1,4 +1,5 @@
 use lsp_types::ClientCapabilities;
+use ruff_linter::display_settings;
 
 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 #[allow(clippy::struct_excessive_bools)]
@@ -65,3 +66,20 @@ impl ResolvedClientCapabilities {
         }
     }
 }
+
+impl std::fmt::Display for ResolvedClientCapabilities {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        display_settings! {
+            formatter = f,
+            namespace = "capabilities",
+            fields = [
+                self.code_action_deferred_edit_resolution,
+                self.apply_edit,
+                self.document_changes,
+                self.workspace_refresh,
+                self.pull_diagnostics,
+            ]
+        };
+        Ok(())
+    }
+}