extension_cli: Include the list of what an extension provides in the generated manifest (#24295)

This PR updates the Zed extension CLI with support for populating the
`provides` field in the generated extension manifest.

This field will contain the set of features that the extension provides.

For example:

```
"provides": ["themes", "icon-themes"]
```

Release Notes:

- N/A

crates/extension_cli/src/main.rs

@@ -1,20 +1,18 @@
-use std::{
-    collections::HashMap,
-    env, fs,
-    path::{Path, PathBuf},
-    process::Command,
-    sync::Arc,
-};
+use std::collections::{BTreeSet, HashMap};
+use std::env;
+use std::fs;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+use std::sync::Arc;
 
 use ::fs::{copy_recursive, CopyOptions, Fs, RealFs};
 use anyhow::{anyhow, bail, Context, Result};
 use clap::Parser;
-use extension::{
-    extension_builder::{CompileExtensionOptions, ExtensionBuilder},
-    ExtensionManifest,
-};
+use extension::extension_builder::{CompileExtensionOptions, ExtensionBuilder};
+use extension::ExtensionManifest;
 use language::LanguageConfig;
 use reqwest_client::ReqwestClient;
+use rpc::ExtensionProvides;
 use tree_sitter::{Language, Query, WasmStore};
 
 #[derive(Parser, Debug)]
@@ -99,6 +97,8 @@ async fn main() -> Result<()> {
         );
     }
 
+    let extension_provides = extension_provides(&manifest);
+
     let manifest_json = serde_json::to_string(&rpc::ExtensionApiManifest {
         name: manifest.name,
         version: manifest.version,
@@ -109,6 +109,7 @@ async fn main() -> Result<()> {
             .repository
             .ok_or_else(|| anyhow!("missing repository in extension manifest"))?,
         wasm_api_version: manifest.lib.version.map(|version| version.to_string()),
+        provides: extension_provides,
     })?;
     fs::remove_dir_all(&archive_dir)?;
     fs::write(output_dir.join("manifest.json"), manifest_json.as_bytes())?;
@@ -116,6 +117,44 @@ async fn main() -> Result<()> {
     Ok(())
 }
 
+/// Returns the set of features provided by the extension.
+fn extension_provides(manifest: &ExtensionManifest) -> BTreeSet<ExtensionProvides> {
+    let mut provides = BTreeSet::default();
+    if !manifest.themes.is_empty() {
+        provides.insert(ExtensionProvides::Themes);
+    }
+
+    if !manifest.icon_themes.is_empty() {
+        provides.insert(ExtensionProvides::IconThemes);
+    }
+
+    if !manifest.languages.is_empty() {
+        provides.insert(ExtensionProvides::Languages);
+    }
+
+    if !manifest.grammars.is_empty() {
+        provides.insert(ExtensionProvides::Grammars);
+    }
+
+    if !manifest.language_servers.is_empty() {
+        provides.insert(ExtensionProvides::LanguageServers);
+    }
+
+    if !manifest.context_servers.is_empty() {
+        provides.insert(ExtensionProvides::ContextServers);
+    }
+
+    if !manifest.indexed_docs_providers.is_empty() {
+        provides.insert(ExtensionProvides::IndexedDocsProviders);
+    }
+
+    if manifest.snippets.is_some() {
+        provides.insert(ExtensionProvides::Snippets);
+    }
+
+    provides
+}
+
 async fn copy_extension_resources(
     manifest: &ExtensionManifest,
     extension_path: &Path,