Remove explicit != methods for Dual (#793)

* Remove explicit `!=` methods for Dual

These are already defined by Base in terms of `==`.

* Bump version

Author: JamesWrigley

Project.toml

@@ -1,6 +1,6 @@
 name = "ForwardDiff"
 uuid = "f6369f11-7733-5829-9624-2563aa707210"
-version = "1.3.1"
+version = "1.3.2"
 
 [deps]
 CommonSubexpressions = "bbf7d656-a473-5ed7-a52c-81e309532950"

src/dual.jl

@@ -391,7 +391,7 @@ for pred in UNARY_PREDICATES
 end
 
 # Before PR#481 this loop ran over this list:
-# BINARY_PREDICATES = Symbol[:isequal, :isless, :<, :>, :(==), :(!=), :(<=), :(>=)]
+# BINARY_PREDICATES = Symbol[:isequal, :isless, :<, :>, :(==), :(<=), :(>=)]
 # Not a minimal set, as Base defines some in terms of others.
 @define_binary_dual_op(
     Base.:(<),
@@ -426,13 +426,6 @@ for pred in [:isequal, :(==)]
     end
 end
 
-@define_binary_dual_op(
-    Base.:(!=),
-    (!=)(value(x), value(y)) || (!=)(partials(x), partials(y)),
-    (!=)(value(x), y)        || !iszero(partials(x)),
-    (!=)(x, value(y))        || !iszero(partials(y)),
-)
-
 ########################
 # Promotion/Conversion #
 ########################