Give every printf-like function restrict qualifiers

The format value has to be a string literal, every time.

Otherwise, you are not using these functions correctly. To reinforce this fact, I putrestrict over every non-contrib example of this I could find.

plugins/audit_json/audit_json.c

@@ -380,7 +380,7 @@ add_timestamp(struct json_container *jsonc, struct timespec *ts)
 }
 
 static int
-audit_write_json(struct json_container *jsonc)
+audit_write_json(struct json_container * restrict jsonc)
 {
     struct stat sb;
     int ret = -1;