Prevent navigable being overridden by parent navigable

Author: whimboo

index.bs

@@ -3030,10 +3030,10 @@ To <dfn>get the navigable info</dfn> given |navigable|,
 
 1. Let |navigable id| be the [=navigable id=] for |navigable|.
 
-1. Let |navigable| be |navigable|'s [=navigable/parent=].
+1. Let |parent navigable| be |navigable|'s [=navigable/parent=].
 
-1. If |navigable| is not null let |parent id| be the
-   [=navigable id=] of |navigable|. Otherwise let
+1. If |parent navigable| is not null let |parent id| be the
+   [=navigable id=] of |parent navigable|. Otherwise let
    |parent id| be null.
 
 1. Let |document| be |navigable|'s [=active document=].