Document the --plain option.

docs.h

@@ -20,6 +20,7 @@ static const char docs_keygen[] =
 "  Generate a brand new keypair.\n"
 "\n"
 "  --force, -f        overwrite any existing keys (default: no clobber)\n"
+"  --plain, -u        don't encrypt the secret key\n"
 "\n"
 "The global --pubkey and --seckey options select the filenames.\n";
 

enchive.c

@@ -573,6 +573,8 @@ command_extract(struct optparse *options)
     int option;
     while ((option = optparse_long(options, extract, 0)) != -1) {
         switch (option) {
+            default:
+                fatal("%s", options->errmsg);
         }
     }