The diff type from a slice/map value should not be forwarded

When a value in a slice/map results in a `TypesDiffer`, the resulting
diff for the slice/map should be ContentDiffer

Author: yazgazan

diff/diff_test.go

@@ -51,7 +51,7 @@ func TestDiff(t *testing.T) {
 			Want: ContentDiffer,
 		},
 		{LHS: []interface{}{1, 2, 3}, RHS: []interface{}{1, 2, 3}, Want: Identical},
-		{LHS: []interface{}{1, 2, 3}, RHS: []interface{}{1, 2, 3.3}, Want: TypesDiffer},
+		{LHS: []interface{}{1, 2, 3}, RHS: []interface{}{1, 2, 3.3}, Want: ContentDiffer},
 		{LHS: []interface{}(nil), RHS: []interface{}{1, 2, 3.3}, Want: ContentDiffer},
 		{LHS: []int(nil), RHS: []int{}, Want: ContentDiffer},
 		{LHS: func() {}, RHS: func() {}, Want: TypesDiffer, Error: true},

diff/map.go

@@ -54,7 +54,7 @@ func NewMap(lhs, rhs interface{}) (*Map, error) {
 					}, err
 				}
 				if diff.Diff() != Identical {
-					Type = diff.Diff()
+					Type = ContentDiffer
 				}
 				diffs[key.Interface()] = diff
 				continue

diff/slice.go

@@ -50,7 +50,7 @@ func NewSlice(lhs, rhs interface{}) (*Slice, error) {
 					}, err
 				}
 				if diff.Diff() != Identical {
-					Type = diff.Diff()
+					Type = ContentDiffer
 				}
 				diffs = append(diffs, diff)
 				continue