Fix for completion after the closing quote in a directive.

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

Index: pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart b/pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart
index 1290f70ae764e4f5f20277db247b9558f8d99439..724e084efb17001f132a4a2eb08bb866fe3e6607 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart
@@ -229,7 +229,13 @@ class DartCompletionRequestImpl implements DartCompletionRequest {
   }
 
   @override
-  String get sourceContents => context.getContents(source)?.data;
+  String get sourceContents {
+    if (result != null) {
+      return result.content;
+    } else {
+      return context.getContents(source)?.data;
+    }
+  }
 
   @override
   SourceFactory get sourceFactory {