patch 7.4.846

Problem:    Some GitHub users don't know how to use issues.
Solution:   Add a file that explains the basics of contributing.

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    846,
 /**/
     845,
 /**/