Fix typo about De Morgan's law assist

cronokirby · web-flow · commit e06ad80d49f6 · 2019-10-04T12:45:22.000+02:00
diff --git a/docs/user/features.md b/docs/user/features.md
@@ -176,7 +176,7 @@ fn example(x: bool) -> bool {
 
 // after:
 fn example(x: bool) -> bool {
-    !(x && !x)
+    !(x && x)
 }
 ```
 
