patch 9.1.0828: string_T struct could be used more often

Problem:  string_T struct could be used more often
Solution: Refactor code and make use of string_T struct
          for key-value pairs, reformat overlong lines
          (John Marriott)

closes: #15975

Signed-off-by: John Marriott <basilisk@internode.on.net>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/syntax.c b/src/syntax.c
index eec5799..6940aa1 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -4066,7 +4066,7 @@
     for (i = 0; i < nr_entries; ++i)
 	if (flags & nlist[i].key)
 	{
-	    msg_puts_attr(nlist[i].value, attr);
+	    msg_puts_attr((char *)nlist[i].value.string, attr);
 	    msg_putchar(' ');
 	}
 }