patch 8.1.1888: more functions can be used as methods

Problem:    More functions can be used as methods.
Solution:   Make various functions usable as a method.
diff --git a/src/version.c b/src/version.c
index eb4106f..85d481a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -766,6 +766,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1888,
+/**/
     1887,
 /**/
     1886,