新增 DefinedIn 注解。

src/main/java/xyz/zhouxy/plusone/commons/annotation/DefinedIn.java

@@ -0,0 +1,12 @@
+package xyz.zhouxy.plusone.commons.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.SOURCE)
+public @interface DefinedIn {
+    Class<?>[] value();
+}