Fix def syntax

Author: Eloitor

example/assoc.bl

@@ -1,23 +1,23 @@
-def (K? to V?) : (Type, Type) -> Type do:
+def K? to V? : (Type, Type) -> Type =
     Map of [(K, V)]
 
-def (group pairs?) do:
+def group pairs? =
     match pairs with:
         () => ()
         x? :: y? :: xs? => (x, y) :: group xs
 
-def (map pairs...?) do:
+def map pairs...? =
     Map of group pairs
 
-def (m? find-key k?) do:
+def m? find-key k? =
     match m with:
         (k, v?) :: xs? => v
         e? :: xs? => xs find-key k
 
-def (m? find k?) : (Any to Any, Any) -> Any do:
+def m? find k? : (Any to Any, Any) -> Any =
     match m with:
         Map of xs? => xs find-key k
 
-def (m? with entry?) : (Any to Any, (Any, Any)) -> Any do:
+def m? with entry? : (Any to Any, (Any, Any)) -> Any =
     match m with:
         Map of xs? => Map of (entry :: xs)