fix comment

paimon-core/src/main/java/org/apache/paimon/utils/BulkFormatMapping.java

@@ -223,7 +223,8 @@ static Pair<int[], RowType> trimKeyFields(
                     } else {
                         map[i] = positionMap.computeIfAbsent(id, k -> trimmedFields.size());
                         // If the target field is not key field, we remain what it is, because it
-                        // may be projected. Ex: the target field is a row type, but only read the
+                        // may be projected. Example: the target field is a row type, but only read
+                        // the
                         // few fields in it. If we simply
                         // trimmedFields.add(f), we will read more fields than we need.
                         trimmedFields.add(keyField ? f : field);