patch 8.1.1158: json encoded string is sometimes missing the final NUL

Problem:    Json encoded string is sometimes missing the final NUL.
Solution:   Add the NUL.  Also for log messages.

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1158,
 /**/
     1157,
 /**/