Update spec/Section 2 -- Language.md

Co-authored-by: Benjie Gillam <[email protected]>

Author: twof

spec/Section 2 -- Language.md

@@ -517,7 +517,9 @@ which returns the result:
 
 ## Nullability
 
-Nullability : (`?`|`!`)
+Nullability :
+  - !
+  - ?
 
 Fields can have their nullability designated with either a `!` to indicate that a
 field should be `Non-Nullable` or a `?` to indicate that a field should be