Use hyphens for property names

- "icon_size" -> "icon-size"

gnucash/gtkbuilder/assistant-csv-trans-import.glade

@@ -416,7 +416,7 @@ There are two reserved names which can't be used to save custom settings:
                             <property name="halign">start</property>
                             <property name="valign">start</property>
                             <property name="icon-name">dialog-information</property>
-                            <property name="icon_size">3</property>
+                            <property name="icon-size">3</property>
                           </object>
                           <packing>
                             <property name="expand">False</property>
@@ -864,7 +864,7 @@ For example
                 <property name="halign">start</property>
                 <property name="valign">start</property>
                 <property name="icon-name">dialog-information</property>
-                <property name="icon_size">3</property>
+                <property name="icon-size">3</property>
               </object>
               <packing>
                 <property name="expand">False</property>

gnucash/gtkbuilder/dialog-commodity.glade

@@ -537,7 +537,7 @@
                         <property name="visible">True</property>
                         <property name="can-focus">False</property>
                         <property name="icon-name">dialog-warning</property>
-                        <property name="icon_size">2</property>
+                        <property name="icon-size">2</property>
                       </object>
                       <packing>
                         <property name="expand">False</property>
@@ -564,7 +564,7 @@
                         <property name="visible">True</property>
                         <property name="can-focus">False</property>
                         <property name="icon-name">dialog-warning</property>
-                        <property name="icon_size">2</property>
+                        <property name="icon-size">2</property>
                       </object>
                       <packing>
                         <property name="expand">False</property>

gnucash/gtkbuilder/dialog-date-close.glade

@@ -73,7 +73,7 @@
                     <property name="visible">True</property>
                     <property name="can-focus">False</property>
                     <property name="icon-name">dialog-question</property>
-                    <property name="icon_size">3</property>
+                    <property name="icon-size">3</property>
                   </object>
                   <packing>
                     <property name="expand">False</property>
@@ -328,7 +328,7 @@
                     <property name="visible">True</property>
                     <property name="can-focus">False</property>
                     <property name="icon-name">dialog-question</property>
-                    <property name="icon_size">3</property>
+                    <property name="icon-size">3</property>
                   </object>
                   <packing>
                     <property name="expand">False</property>

gnucash/gtkbuilder/dialog-invoice.glade

@@ -1365,7 +1365,7 @@
                     <property name="visible">True</property>
                     <property name="can-focus">False</property>
                     <property name="icon-name">dialog-question</property>
-                    <property name="icon_size">3</property>
+                    <property name="icon-size">3</property>
                   </object>
                   <packing>
                     <property name="expand">False</property>

gnucash/gtkbuilder/dialog-new-user.glade

@@ -73,7 +73,7 @@
                 <property name="visible">True</property>
                 <property name="can-focus">False</property>
                 <property name="icon-name">go-home</property>
-                <property name="icon_size">6</property>
+                <property name="icon-size">6</property>
               </object>
               <packing>
                 <property name="left-attach">0</property>
@@ -196,7 +196,7 @@
                 <property name="visible">True</property>
                 <property name="can-focus">False</property>
                 <property name="icon-name">go-home</property>
-                <property name="icon_size">6</property>
+                <property name="icon-size">6</property>
               </object>
               <packing>
                 <property name="left-attach">0</property>

gnucash/gtkbuilder/dialog-preferences.glade

@@ -878,7 +878,7 @@ Press 'Close' to return to the preference window
                         <property name="can-focus">False</property>
                         <property name="halign">start</property>
                         <property name="icon-name">dialog-warning</property>
-                        <property name="icon_size">3</property>
+                        <property name="icon-size">3</property>
                       </object>
                       <packing>
                         <property name="expand">False</property>

gnucash/import-export/aqb/dialog-ab.glade

@@ -735,7 +735,7 @@
                     <property name="hexpand">True</property>
                     <property name="vexpand">True</property>
                     <property name="icon-name">image-missing</property>
-                    <property name="icon_size">6</property>
+                    <property name="icon-size">6</property>
                   </object>
                   <packing>
                     <property name="expand">False</property>