Auto-update style.md

Author: gonzaloserrano

style.md

@@ -3896,6 +3896,10 @@ While there are no strict guidelines, readability and maintainability should
 always be top-of-mind when deciding between Table Tests versus separate tests
 for multiple inputs/outputs to a system.
 
+#### Parallel Tests
+
+Run `t.Parallel()` to improve the performance of your test cases.
+
 <!-- TODO: Explain how to use _test packages. -->
 
 ### Functional Options