Document command parameters.

Add documentation for all commands that have parameters.
Fix a couple of minor doc and programming bugs, too.

Fixes #10313

Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/10371)

apps/kdf.c

diff --git a/apps/kdf.c b/apps/kdf.c
index abd21ce..66e7e7a 100644
--- a/apps/kdf.c
+++ b/apps/kdf.c
@@ -24,18 +24,20 @@
 
 const OPTIONS kdf_options[] = {
     {OPT_HELP_STR, 1, '-', "Usage: %s [options] kdf_name\n"},
-    {OPT_HELP_STR, 1, '-', "kdf_name\t KDF algorithm.\n"},
 
     OPT_SECTION("General"),
     {"help", OPT_HELP, '-', "Display this summary"},
-    {"kdfopt", OPT_KDFOPT, 's', "KDF algorithm control parameters in n:v form."},
-    {OPT_HELP_STR, 1, '-', "See 'Supported Controls' in the EVP_KDF_ docs"},
+    {"kdfopt", OPT_KDFOPT, 's', "KDF algorithm control parameters in n:v form"},
+    {OPT_MORE_STR, 1, '-', "See 'Supported Controls' in the EVP_KDF_ docs\n"},
     {"keylen", OPT_KEYLEN, 's', "The size of the output derived key"},
 
     OPT_SECTION("Output"),
     {"out", OPT_OUT, '>', "Output to filename rather than stdout"},
-    {"binary", OPT_BIN, '-', "Output in binary format (Default is hexadecimal "
-                             "output)"},
+    {"binary", OPT_BIN, '-',
+        "Output in binary format (default is hexadecimal)"},
+
+    OPT_PARAMETERS(),
+    {"kdf_name", 0, 0, "Name of the KDF algorithm"},
     {NULL}
 };