patch 8.2.0257: cannot recognize a terminal in a popup window

Problem:    Cannot recognize a terminal in a popup window.
Solution:   Add the win_gettype() function.
diff --git a/src/version.c b/src/version.c
index 73ea736..70ea449 100644
--- a/src/version.c
+++ b/src/version.c
@@ -743,6 +743,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    257,
+/**/
     256,
 /**/
     255,