Fix exception name

Author: kevmoo

example/lib/sealed_class_example.g.dart

@@ -81,7 +81,7 @@ class UnrecognizedKeysException extends BadKeyException {
 
 /// Exception thrown if there is an unrecognized union type in a JSON map
 /// that was provided during deserialization.
-class UnrerecognizedUnionTypeException extends BadKeyException {
+class UnrecognizedUnionTypeException extends BadKeyException {
   /// The discriminator that was not recognized.
   final String unrecognizedType;
 
@@ -92,8 +92,7 @@ class UnrerecognizedUnionTypeException extends BadKeyException {
   String get message => 'Unrecognized type: $unrecognizedType '
       'for union: $unionType.';
 
-  UnrerecognizedUnionTypeException(
-      this.unrecognizedType, this.unionType, Map map)
+  UnrecognizedUnionTypeException(this.unrecognizedType, this.unionType, Map map)
       : super._(map);
 }
 

json_annotation/lib/src/allowed_keys_helpers.dart

@@ -163,7 +163,7 @@ mixin DecodeHelper implements HelperCore {
       ..write("switch (json['$discriminator']) {")
       ..writeAll(implementations.map(buildSingleImpl), '\n')
       ..writeln('''
-_ => throw UnrerecognizedUnionTypeException(
+_ => throw UnrecognizedUnionTypeException(
   '\${json['$discriminator']}', 
   ${element.name},
   json,