Expose context server settings to extensions (#20555)

This PR exposes context server settings to extensions.

Extensions can use `ContextServerSettings::for_project` to get the
context server settings for the current project.

The `experimental.context_servers` setting has been removed and replaced
with the `context_servers` setting (which is now an object instead of an
array).

Release Notes:

- N/A

---------

Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>

crates/extension_api/wit/since_v0.2.0/extension.wit

@@ -83,6 +83,12 @@ world extension {
         shell-env: func() -> env-vars;
     }
 
+    /// A Zed project.
+    resource project {
+        /// Returns the IDs of all of the worktrees in this project.
+        worktree-ids: func() -> list<u64>;
+    }
+
     /// A key-value store.
     resource key-value-store {
         /// Inserts an entry under the specified key.
@@ -136,7 +142,7 @@ world extension {
     export run-slash-command: func(command: slash-command, args: list<string>, worktree: option<borrow<worktree>>) -> result<slash-command-output, string>;
 
     /// Returns the command used to start up a context server.
-    export context-server-command: func(context-server-id: string) -> result<command, string>;
+    export context-server-command: func(context-server-id: string, project: borrow<project>) -> result<command, string>;
 
     /// Returns a list of packages as suggestions to be included in the `/docs`
     /// search results.

crates/extension_api/wit/since_v0.2.0/settings.rs

@@ -1,5 +1,5 @@
 use serde::{Deserialize, Serialize};
-use std::num::NonZeroU32;
+use std::{collections::HashMap, num::NonZeroU32};
 
 /// The settings for a particular language.
 #[derive(Debug, Serialize, Deserialize)]
@@ -12,18 +12,29 @@ pub struct LanguageSettings {
 #[derive(Default, Debug, Serialize, Deserialize)]
 pub struct LspSettings {
     /// The settings for the language server binary.
-    pub binary: Option<BinarySettings>,
+    pub binary: Option<CommandSettings>,
     /// The initialization options to pass to the language server.
     pub initialization_options: Option<serde_json::Value>,
     /// The settings to pass to language server.
     pub settings: Option<serde_json::Value>,
 }
 
-/// The settings for a language server binary.
-#[derive(Debug, Serialize, Deserialize)]
-pub struct BinarySettings {
-    /// The path to the binary.
-    pub path: Option<String>,
-    /// The arguments to pass to the binary.
-    pub arguments: Option<Vec<String>>,
+/// The settings for a particular context server.
+#[derive(Default, Debug, Serialize, Deserialize, PartialEq, Eq)]
+pub struct ContextServerSettings {
+    /// The settings for the context server binary.
+    pub command: Option<CommandSettings>,
+    /// The settings to pass to the context server.
+    pub settings: Option<serde_json::Value>,
+}
+
+/// The settings for a command.
+#[derive(Debug, Serialize, Deserialize, PartialEq, Eq)]
+pub struct CommandSettings {
+    /// The path to the command.
+    pub path: Option<String>,
+    /// The arguments to pass to the command.
+    pub arguments: Option<Vec<String>>,
+    /// The environment variables.
+    pub env: Option<HashMap<String, String>>,
 }