[gnome-calculator] Use consistent spacing in functions and variables popover (#76)

[Robert Roth <robertroth src gnome org>]

commit bed2cdddd781b89bc15ab39ab927ca691ffa2e65
Author: Robert Roth <robert roth off gmail com>
Date:   Thu Oct 4 21:47:11 2018 +0300

    Use consistent spacing in functions and variables popover (#76)

 src/math-function-popover.ui | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/math-function-popover.ui b/src/math-function-popover.ui
index b103dd4d..3cc88b76 100644
--- a/src/math-function-popover.ui
+++ b/src/math-function-popover.ui
@@ -48,6 +48,7 @@
             <child>
               <object class="GtkSpinButton" id="add_arguments_button">
                 <property name="visible">True</property>
+                <property name="expand">True</property>
                 <property name="can_focus">True</property>
               </object>
             </child>