[fixes #2838] Handle anonymous classes properly

Generated qualified names (e.g. Outer.Inner) now stop at anonymous
classes instead of adding an empty part. All handlers that add static
fields/methods/types now add error messages instead of generating
invalid code.

test/transform/resource/after-ecj/LoggerSlf4jInAnonymousClass.java

@@ -0,0 +1,16 @@
+import lombok.extern.slf4j.Slf4j;
+public class LoggerSlf4jInAnonymousClass {
+  Object annonymous = new Object() {
+    @Slf4j class Inner {
+      Inner() {
+        super();
+      }
+    }
+    x() {
+      super();
+    }
+  };
+  public LoggerSlf4jInAnonymousClass() {
+    super();
+  }
+}