Provide JSON language server with settings schema

crates/language/src/language.rs

@@ -95,6 +95,8 @@ pub trait LspAdapter: 'static + Send + Sync {
     fn initialization_options(&self) -> Option<Value> {
         None
     }
+
+    fn register_handlers(&self, _: &mut lsp::LanguageServer) {}
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -319,13 +321,15 @@ impl LanguageRegistry {
 
             let server_binary_path = server_binary_path.await?;
             let server_args = adapter.server_args();
-            lsp::LanguageServer::new(
+            let mut server = lsp::LanguageServer::new(
                 &server_binary_path,
                 server_args,
                 &root_path,
                 adapter.initialization_options(),
                 background,
-            )
+            )?;
+            adapter.register_handlers(&mut server);
+            Ok(server)
         }))
     }