Tweaks for hover.

pkg/analyzer/lib/src/generated/element.dart

Index: pkg/analyzer/lib/src/generated/element.dart
diff --git a/pkg/analyzer/lib/src/generated/element.dart b/pkg/analyzer/lib/src/generated/element.dart
index fcf25110d23a388633113f7990b7569f9b3028b9..6f459991ceee484a681e41aa3c45679f8f4ea547 100644
--- a/pkg/analyzer/lib/src/generated/element.dart
+++ b/pkg/analyzer/lib/src/generated/element.dart
@@ -814,6 +814,10 @@ class ClassElementImpl extends ElementImpl implements ClassElement {
 
   @override
   void appendTo(StringBuffer buffer) {
+    if (isAbstract) {
+      buffer.write('abstract ');
+    }
+    buffer.write('class ');
     String name = displayName;
     if (name == null) {
       buffer.write("{unnamed class}");
@@ -831,6 +835,18 @@ class ClassElementImpl extends ElementImpl implements ClassElement {
       }
       buffer.write(">");
     }
+    if (supertype != null && !supertype.isObject) {
+      buffer.write(' extends ');
+      buffer.write(supertype.displayName);
+    }
+    if (mixins.isNotEmpty) {
+      buffer.write(' with ');
+      buffer.write(mixins.map((t) => t.displayName).join(', '));
+    }
+    if (interfaces.isNotEmpty) {
+      buffer.write(' implements ');
+      buffer.write(interfaces.map((t) => t.displayName).join(', '));
+    }
   }
 
   @override