identifiers: Merge more impl blocks

crates/ruma-identifiers/src/event_id.rs

@@ -65,9 +65,7 @@ impl EventId {
 
         Self { full_id, colon_idx: NonZeroU8::new(19) }
     }
-}
 
-impl EventId {
     /// Returns the event's unique ID. For the original event format as used by Matrix room
     /// versions 1 and 2, this is the "localpart" that precedes the homeserver. For later formats,
     /// this is the entire ID without the leading $ sigil.

crates/ruma-identifiers/src/room_id.rs

@@ -43,9 +43,7 @@ impl RoomId {
 
         Self { full_id, colon_idx: NonZeroU8::new(19).unwrap() }
     }
-}
 
-impl RoomId {
     /// Returns the rooms's unique ID.
     pub fn localpart(&self) -> &str {
         &self.full_id[1..self.colon_idx.get() as usize]