Use IDL this for the synthetic forEach method.

Author: Ms2ger

index.bs

@@ -11538,7 +11538,6 @@ then the [=function object=] is {{%ArrayProto_forEach%}}.
 
     with the following prose definition:
 
-    1.  Let |O| be the <emu-val>this</emu-val> value.
     1.  Let |pairs| be the list of [=value pairs to iterate over=].
     1.  Let |i| be 0.
     1.  While |i| is less than the length of |pairs|:
@@ -11547,8 +11546,7 @@ then the [=function object=] is {{%ArrayProto_forEach%}}.
         1.  Let |value| be |pair|’s value.
         1.  [=Invoke=] |callback| with |thisArg|
             (or <emu-val>undefined</emu-val>, if the argument was not supplied)
-            as the [=callback this value|callback this value=] and
-            |value|, |key| and |O| as its arguments.
+            as the [=callback this value=] and |value|, |key| and <b>this</b> as its arguments.
         1.  Update |pairs| to the current list of [=value pairs to iterate over=].
         1.  Set |i| to |i| + 1.
 </div>