[Change] 调整搜索接口返回数据中Attribute的Enum存放位置;

[Change] PixivSearchLinkBuilder 调整SuppressWarnings注解;
[Deprecated] PixivSearchLinkBuilder.SearchArea.jsonKey 将属性标记deprecated;
[Add] PixivSearchAttribute 增加搜索结果属性枚举类, 用于代替`PixivSearchLinkBuilder.SearchArea.jsonKey`;

src/main/java/net/lamgc/cgj/pixiv/PixivSearchLinkBuilder.java

@@ -15,7 +15,7 @@ import java.util.Objects;
  * @author LamGC
  * @see PixivURL#PIXIV_SEARCH_CONTENT_URL
  */
-@SuppressWarnings("unused")
+@SuppressWarnings({"unused", "UnusedReturnValue"})
 public class PixivSearchLinkBuilder {
 
     private final String content;
@@ -296,13 +296,18 @@ public class PixivSearchLinkBuilder {
          */
         NOVELS("novel");
 
+        /**
+         * 可用的Json属性名
+         * @deprecated 该属性信息以移至 {@link PixivSearchAttribute}
+         * @see PixivSearchAttribute
+         */
+        @Deprecated
         public final String jsonKey;
 
         SearchArea(String jsonKey) {
             this.jsonKey = jsonKey;
         }
 
-
     }
 
     /**