fix(zapio): address all sywhang review comments

- Remove unnecessary comment parameters in flush calls
- Ensure code style consistency

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: lyydsheep <2230561977@qq.com>

Author: lyydsheep

zapio/writer.go

@@ -124,7 +124,7 @@ func (w *Writer) writeLine(line []byte) (remaining []byte) {
 	w.buff.Write(line)
 	// Log empty messages in the middle of the stream so that we don't lose
 	// information when the user writes "foo\n\nbar".
-	w.flush(true /* allowEmpty */)
+	w.flush(true)
 	return remaining
 }
 
@@ -142,7 +142,7 @@ func (w *Writer) Sync() error {
 	// Don't allow empty messages on explicit Sync calls or on Close
 	// because we don't want an extraneous empty message at the end of the
 	// stream -- it's common for files to end with a newline.
-	w.flush(false /* allowEmpty */)
+	w.flush(false)
 	return nil
 }