Parse repeatable directive definitions

src/Language/GraphQL/AST/Encoder.hs

@@ -159,11 +159,12 @@ typeSystemDefinition formatter = \case
             <> optempty (directives formatter) operationDirectives
             <> bracesList formatter (operationTypeDefinition formatter) (NonEmpty.toList operationTypeDefinitions')
     Full.TypeDefinition typeDefinition' -> typeDefinition formatter typeDefinition'
-    Full.DirectiveDefinition description' name' arguments' locations
+    Full.DirectiveDefinition description' name' arguments' repeatable locations
         -> description formatter description'
         <> "@"
         <> Lazy.Text.fromStrict name'
         <> argumentsDefinition formatter arguments'
+        <> (if repeatable then " repeatable" else mempty)
         <> " on"
         <> pipeList formatter (directiveLocation <$> locations)