patch 8.1.1909: more functions can be used as methods

Problem:    More functions can be used as methods.
Solution:   Make a few more functions usable as a method.
diff --git a/src/version.c b/src/version.c
index a6544cd..37b0f79 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1909,
+/**/
     1908,
 /**/
     1907,