[gnome-calculator] List possible modes in command line help (fixes #122)

[Robert Roth <robertroth src gnome org>]

commit d51c1bfc72b64887522f93b1219fc587656ef0c1
Author: Robert Roth <robert roth off gmail com>
Date:   Thu Oct 3 22:22:18 2019 +0300

    List possible modes in command line help (fixes #122)

 src/gnome-calculator.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/gnome-calculator.vala b/src/gnome-calculator.vala
index 60b072d8..be9e84d1 100644
--- a/src/gnome-calculator.vala
+++ b/src/gnome-calculator.vala
@@ -21,7 +21,7 @@ public class Calculator : Gtk.Application
     private static string mode_string = null;
 
     private const OptionEntry[] option_entries = {
-        { "mode", 'm', 0, OptionArg.STRING, ref mode_string, N_("Start in given mode"), "mode" },
+        { "mode", 'm', 0, OptionArg.STRING, ref mode_string, N_("Start in given mode (basic, advanced, 
financial, programming, keyboard)"), "mode" },
         { "solve", 's', 0, OptionArg.STRING, null, N_("Solve given equation"), "equation" },
         { "equation", 'e', 0, OptionArg.STRING, ref equation_string, N_("Start with given equation"), 
"equation"},
         { "version", 'v', 0, OptionArg.NONE, null, N_("Show release version"), null },