[CALCITE-4314] Use exact parameter names in JavaDoc

See https://errorprone.info/bugpattern/InvalidParam

linq4j/src/main/java/org/apache/calcite/linq4j/EnumerableDefaults.java

@@ -4320,8 +4320,8 @@ private boolean advance() {
 
 
     /**
-     * Clears {@code lefts} list, adds {@code left} into it, and advance left enumerator,
-     * adding all items with the same key to {@code lefts} list too, until left enumerator
+     * Clears {@code left} list, adds {@code left} into it, and advance left enumerator,
+     * adding all items with the same key to {@code left} list too, until left enumerator
      * is over or a different key is found.
      * @return {@code true} if there are still elements to be processed on the left enumerator,
      * {@code false} otherwise (left enumerator is over or null key is found).
@@ -4352,8 +4352,8 @@ private boolean advanceLeft(TSource left, TKey leftKey) {
     }
 
     /**
-     * Clears {@code rights} list, adds {@code right} into it, and advance right enumerator,
-     * adding all items with the same key to {@code rights} list too, until right enumerator
+     * Clears {@code right} list, adds {@code right} into it, and advance right enumerator,
+     * adding all items with the same key to {@code right} list too, until right enumerator
      * is over or a different key is found.
      * @return {@code true} if there are still elements to be processed on the right enumerator,
      * {@code false} otherwise (right enumerator is over or null key is found).