fix: Correct relations pagination and recursion

Ended up rewriting a fair bit, but should work better.

src/core/matrix/event/relation.rs

@@ -8,7 +8,7 @@ pub trait RelationTypeEqual<E: Event> {
 }
 
 #[derive(Clone, Debug, Deserialize)]
-struct ExtractRelatesToEventId {
+struct ExtractRelatesToRelType {
 	#[serde(rename = "m.relates_to")]
 	relates_to: ExtractRelType,
 }
@@ -18,11 +18,16 @@ struct ExtractRelType {
 	rel_type: RelationType,
 }
 
+/// The type of an event's relation, if it has one
+pub fn relation_type<E: Event>(event: &E) -> Option<RelationType> {
+	event
+		.get_content()
+		.map(|c: ExtractRelatesToRelType| c.relates_to.rel_type)
+		.ok()
+}
+
 impl<E: Event> RelationTypeEqual<E> for RelationType {
 	fn relation_type_equal(&self, event: &E) -> bool {
-		event
-			.get_content()
-			.map(|c: ExtractRelatesToEventId| c.relates_to.rel_type)
-			.is_ok_and(|r| r == *self)
+		relation_type(event).is_some_and(|r| r == *self)
 	}
 }