refactor(sync): drop storeHeaders helper (#193)

## Overview

Make `store` field usage explicit. Plus `storeHeaders` was just a
wrapper around `store.Append` without any logic.

Author: cristaloleg

sync/sync.go

@@ -290,7 +290,7 @@ func (s *Syncer[H]) processHeaders(
 		}
 
 		// apply cached headers
-		if err = s.storeHeaders(ctx, headers...); err != nil {
+		if err := s.store.Append(ctx, headers...); err != nil {
 			return err
 		}
 
@@ -325,7 +325,7 @@ func (s *Syncer[H]) requestHeaders(
 			return err
 		}
 
-		if err := s.storeHeaders(ctx, headers...); err != nil {
+		if err := s.store.Append(ctx, headers...); err != nil {
 			return err
 		}
 
@@ -334,14 +334,3 @@ func (s *Syncer[H]) requestHeaders(
 	}
 	return nil
 }
-
-// storeHeaders updates store with new headers and updates current syncStore's Head.
-func (s *Syncer[H]) storeHeaders(ctx context.Context, headers ...H) error {
-	// we don't expect any issues in storing right now, as all headers are now verified.
-	// So, we should return immediately in case an error appears.
-	err := s.store.Append(ctx, headers...)
-	if err != nil {
-		return err
-	}
-	return nil
-}

sync/sync_head.go

@@ -118,7 +118,7 @@ func (s *Syncer[H]) setSubjectiveHead(ctx context.Context, netHead H) {
 	//  * Allow storing any valid header here in Store
 	//  * Remove ErrNonAdjacent
 	//  * Remove writeHead from the canonical store implementation
-	err := s.storeHeaders(ctx, netHead)
+	err := s.store.Append(ctx, netHead)
 	var nonAdj *header.ErrNonAdjacent
 	if err != nil && !errors.As(err, &nonAdj) {
 		// might be a storage error or something else, but we can still try to continue processing netHead