patch 8.1.1880: cannot show extra info for completion in a popup window

Problem:    Cannot show extra info for completion in a popup window.
Solution:   Add the "popup" entry in 'completeopt'.
diff --git a/src/version.c b/src/version.c
index 8005f1f..0611690 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1880,
+/**/
     1879,
 /**/
     1878,