add constructor initializer completions

pkg/analysis_server/lib/src/services/completion/dart/keyword_contributor.dart

Index: pkg/analysis_server/lib/src/services/completion/dart/keyword_contributor.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/keyword_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/keyword_contributor.dart
index 04e79b87d3f76b6dc964a6b3be9a7d93922b5c91..bdce36175badd5ef816d3120aacd4b67c3ef4b89 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/keyword_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/keyword_contributor.dart
@@ -202,6 +202,13 @@ class _KeywordVisitor extends GeneralizingAstVisitor {
   }
 
   @override
+  visitConstructorDeclaration(ConstructorDeclaration node) {
+    if (node.initializers.isNotEmpty && node.initializers.last == entity) {
+      _addSuggestion(Keyword.SUPER);
+    }
+  }
+
+  @override
   visitExpression(Expression node) {
     _addExpressionKeywords(node);
   }