patch 8.2.3880: Solution filter files are not recognized

Problem:    Solution filter files are not recognized.
Solution:   Add pattern *.slnf and use json. (Doug Kearns)
diff --git a/src/version.c b/src/version.c
index 20c78d7..6b4708d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -750,6 +750,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3880,
+/**/
     3879,
 /**/
     3878,