patch 7.4.2072

Problem:    substitute() does not support a Funcref argument.
Solution:   Support a Funcref like it supports  a string starting with "\=".

src/version.c

@@ -758,6 +758,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2072,
 /**/
     2071,
 /**/