suggest this keyword in constructor param list

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

Index: pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart b/pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart
index a202fba4da25145b2ba987049e40f385a5c66bd5..c38a01f647546cd978026b9d8b93bdad0fd28591 100644
--- a/pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart
@@ -118,6 +118,15 @@ class _KeywordVisitor extends GeneralizingAstVisitor {
   }
 
   @override
+  visitFormalParameterList(FormalParameterList node) {
+    AstNode constructorDecl =
+        node.getAncestor((p) => p is ConstructorDeclaration);
+    if (constructorDecl != null) {
+      _addSuggestions([Keyword.THIS]);
+    }
+  }
+
+  @override
   visitIfStatement(IfStatement node) {
     if (entity == node.thenStatement) {
       _addStatementKeywords(node);