GH932: Add more help messages to some apps options.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/apps/pkeyutl.c b/apps/pkeyutl.c
index fe7f586..7c54ec6 100644
--- a/apps/pkeyutl.c
+++ b/apps/pkeyutl.c
@@ -109,7 +109,7 @@
     {"sigfile", OPT_SIGFILE, '<', "Signature file (verify operation only)"},
     {"inkey", OPT_INKEY, 's', "Input private key file"},
     {"peerkey", OPT_PEERKEY, 's', "Peer key file used in key derivation"},
-    {"passin", OPT_PASSIN, 's', "Pass phrase source"},
+    {"passin", OPT_PASSIN, 's', "Input file pass phrase source"},
     {"peerform", OPT_PEERFORM, 'E', "Peer key format - default PEM"},
     {"keyform", OPT_KEYFORM, 'E', "Private key format - default PEM"},
     {"pkeyopt", OPT_PKEYOPT, 's', "Public key options as opt:value"},