patch 8.2.3543: swapname has double slash when 'directory' ends in it

Problem:    Swapname has double slash when 'directory' ends in double slash.
            (Shane Smith)
Solution:   Remove the superfluous slash. (closes #8876)

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3543,
 /**/
     3542,
 /**/