Add Buffer::outline method

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

crates/zed/src/language.rs

@@ -24,6 +24,8 @@ fn rust() -> Language {
         .unwrap()
         .with_indents_query(load_query("rust/indents.scm").as_ref())
         .unwrap()
+        .with_outline_query(load_query("rust/outline.scm").as_ref())
+        .unwrap()
 }
 
 fn markdown() -> Language {

crates/zed/src/main.rs

@@ -59,6 +59,7 @@ fn main() {
         go_to_line::init(cx);
         file_finder::init(cx);
         chat_panel::init(cx);
+        outline::init(cx);
         project_panel::init(cx);
         diagnostics::init(cx);
         cx.spawn({