patch 9.1.0652: too many strlen() calls in syntax.c

Problem:  too many strlen() calls in syntax.c
Solution: refactor code to reduce the number or strlen() calls,
          get rid of un-used SYN_NAMELEN macro
          (John Marriott)

closes: #15368

Signed-off-by: John Marriott <basilisk@internode.on.net>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    652,
 /**/
     651,
 /**/