Fixes a `plug' bug.

There are still problems with contexts, but this is an improvement.

collects/redex/private/matcher.rkt

@@ -1566,7 +1566,7 @@ before the pattern compiler is invoked.
             (cons (loop (car exp))
                   (loop (cdr exp)))]
            [(eq? the-not-hole exp)
-            the-hole]
+            the-not-hole]
            [(eq? the-hole exp)
             (if done?
                 exp

collects/redex/tests/tl-test.rkt

@@ -99,9 +99,7 @@
                                             (define-language x (e ....))
                                             12)))
         '("...."))
-  
-
-  
+ 
   ;; test multiple variable non-terminals
   (let ()
     (define-language lang
@@ -898,6 +896,17 @@
          '())
         '(()))
   
+  (test (apply-reduction-relation
+         (reduction-relation
+          empty-language
+          (--> (in-hole (name E
+                              (in-hole ((hide-hole hole) hole)
+                                       hole))
+                        number)
+               (in-hole E ,(add1 (term number)))))
+         (term (hole 2)))
+        (list (term (hole 3))))
+  
   (test (apply-reduction-relation/tag-with-names
          (reduction-relation 
           grammar