add type completions after "on" in a try block

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

Index: pkg/analysis_server/lib/src/services/completion/optype.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/optype.dart b/pkg/analysis_server/lib/src/services/completion/optype.dart
index d2d6f6c78e0bb8fcc8ec56f7b7e334979449b277..1ed85d523e6e7fd68e700924e793fdf7acbd165e 100644
--- a/pkg/analysis_server/lib/src/services/completion/optype.dart
+++ b/pkg/analysis_server/lib/src/services/completion/optype.dart
@@ -166,6 +166,13 @@ class _OpTypeAstVisitor extends GeneralizingAstVisitor {
   }
 
   @override
+  void visitCatchClause(CatchClause node) {
+    if (identical(entity, node.exceptionType)) {
+      optype.includeTypeNameSuggestions = true;
+    }
+  }
+
+  @override
   void visitClassDeclaration(ClassDeclaration node) {
     // Make suggestions in the body of the class declaration
     if (node.members.contains(entity) || identical(entity, node.rightBracket)) {