[gnome-calculator] Added mnemonic for the exchange rate refresh interval

[Robert Roth <robertroth src gnome org>]

commit 253cac23495760891829b2e8a72dc3c9f35b1cec
Author: Robert Roth <robert roth bee-tf ro>
Date:   Mon Feb 4 19:32:14 2019 +0200

    Added mnemonic for the exchange rate refresh interval

 src/math-preferences.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/math-preferences.vala b/src/math-preferences.vala
index 27a735fc..b67ebb75 100644
--- a/src/math-preferences.vala
+++ b/src/math-preferences.vala
@@ -184,7 +184,7 @@ public class MathPreferencesDialog : Gtk.Dialog
         word_size_combo.add_attribute (renderer, "text", 0);
 
         label = new Gtk.Label.with_mnemonic (/* Preferences dialog: Label for exchange rate refresh interval 
combo box */
-                                             _("Exchange rate refresh interval"));
+                                             _("E_xchange rate refresh interval"));
         label.show ();
         label.xalign = 0;
         grid.attach (label, 0, 7, 1, 1);