Typo fix

src/InductiveTypes.v

@@ -944,7 +944,7 @@ Check nat_tree_ind.
 
 There is no command like [Scheme] that will implement an improved principle for us.  In general, it takes creativity to figure out _good_ ways to incorporate nested uses of different type families.  Now that we know how to implement induction principles manually, we are in a position to apply just such creativity to this problem.
 
-Many induction principles for types with nested used of [list] could benefit from a unified predicate capturing the idea that some property holds of every element in a list.  By defining this generic predicate once, we facilitate reuse of library theorems about it.  (Here, we are actually duplicating the standard library's [Forall] predicate, with a different implementation, for didactic purposes.) *)
+Many induction principles for types with nested uses of [list] could benefit from a unified predicate capturing the idea that some property holds of every element in a list.  By defining this generic predicate once, we facilitate reuse of library theorems about it.  (Here, we are actually duplicating the standard library's [Forall] predicate, with a different implementation, for didactic purposes.) *)
 
 Section All.
   Variable T : Set.