Validation result docs

graphql_schema/lib/src/validation_result.dart

@@ -1,8 +1,14 @@
 part of graphql_schema.src.schema;
 
-class ValidationResult<T> {
+/// Represents the result of asserting an input [value] against a [GraphQLType].
+class ValidationResult<Value> {
+  /// `true` if there were no errors during validation.
   final bool successful;
-  final T value;
+
+  /// The input value passed to whatever caller invoked validation.
+  final Value value;
+
+  /// A list of errors that caused validation to fail.
   final List<String> errors;
 
   ValidationResult._(this.successful, this.value, this.errors);