patch 8.1.1364: design for popup window support needs more details

Problem:    Design for popup window support needs more details.
Solution:   Add details about using a window and buffer.  Rename popup_show()
            to popup_create() and add popup_show() and popup_hide().
diff --git a/src/version.c b/src/version.c
index fb7dad3..b0736df 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1364,
+/**/
     1363,
 /**/
     1362,