Update functional/stateful-types.md

Author: simonsan

functional/stateful-types.md

@@ -237,7 +237,8 @@ transitions, an `InvalidState` enum value in an error type might be simpler.
 
 There are a number of simpler state machines, however, that have their own patterns:
 
-1. If the state transition is during construction/finalizing of an object, see [Builder Pattern](../patterns/creational/builder.md).
+1. If the state transition is during construction/finalizing of an object, see
+[Builder Pattern](../patterns/creational/builder.md).
 1. If the state transitions don't change invariants much, see [Strategy Pattern](../patterns/behavioural/strategy.md).
 
 ## See also