Fixed more compile time errors

src/service/rooms/search/mod.rs

@@ -1,12 +1,14 @@
 mod data;
 pub use data::Data;
+
+use crate::Result;
 use ruma::RoomId;
 
 pub struct Service<D: Data> {
     db: D,
 }
 
-impl Service<_> {
+impl<D: Data> Service<D> {
     #[tracing::instrument(skip(self))]
     pub fn search_pdus<'a>(
         &'a self,