If apropos(1) finds no match, print "nothing appropriate" to stderr

similar to what the old apropos did.
Requested by and OK deraadt@.

1 files changed, 2 insertions, 0 deletions

diff --git a/main.c b/main.c
index ed73e687..261bf4b7 100644
--- a/main.c
+++ b/main.c
@@ -357,6 +357,8 @@ main(int argc, char *argv[])
 			    argc, argv, &res, &sz);
 
 		if (sz == 0) {
+			fprintf(stderr, "%s: nothing appropriate\n",
+			    progname);
 			rc = MANDOCLEVEL_BADARG;
 			goto out;
 		}