/sso/logout 接口 self 格式设置响应头，以适配 solon 下集成 sso 插件可以正常跳转路径

sa-token-plugin/sa-token-sso/src/main/java/cn/dev33/satoken/sso/processor/SaSsoProcessorHelper.java

@@ -47,6 +47,7 @@ public class SaSsoProcessorHelper {
 		String back = req.getParam(paramName.back);
 		if(SaFoxUtil.isNotEmpty(back)) {
 			if(back.equals(SaSsoConsts.SELF)) {
+				res.setHeader("Content-Type", "text/html; charset=utf-8");
 				return "<script>if(document.referrer != location.href){ location.replace(document.referrer || '/'); }</script>";
 			}
 			return res.redirect(back);