Rewrite usage info in help

src/Options.hs

@@ -157,4 +157,5 @@ parseArgs = do
             (_, _, errs) -> return $ Left $ concat errs
 
 usageInformation :: String
-usageInformation = usageInfo "Peregrine" options
+usageInformation =
+        usageInfo ("Usage: peregrine [OPTIONS] FILE\n") options