add : in gajim themes window

src/gtkgui.glade

@@ -15989,7 +15989,7 @@ Banner</property>
 		    <widget class="GtkCheckButton" id="textcolor_checkbutton">
 		      <property name="visible">True</property>
 		      <property name="can_focus">True</property>
-		      <property name="label" translatable="yes">Text _color</property>
+		      <property name="label" translatable="yes">Text _color:</property>
 		      <property name="use_underline">True</property>
 		      <property name="relief">GTK_RELIEF_NORMAL</property>
 		      <property name="focus_on_click">True</property>
@@ -16012,7 +16012,7 @@ Banner</property>
 		    <widget class="GtkCheckButton" id="background_checkbutton">
 		      <property name="visible">True</property>
 		      <property name="can_focus">True</property>
-		      <property name="label" translatable="yes">_Background</property>
+		      <property name="label" translatable="yes">_Background:</property>
 		      <property name="use_underline">True</property>
 		      <property name="relief">GTK_RELIEF_NORMAL</property>
 		      <property name="focus_on_click">True</property>
@@ -16035,7 +16035,7 @@ Banner</property>
 		    <widget class="GtkCheckButton" id="textfont_checkbutton">
 		      <property name="visible">True</property>
 		      <property name="can_focus">True</property>
-		      <property name="label" translatable="yes">Text _font</property>
+		      <property name="label" translatable="yes">Text _font:</property>
 		      <property name="use_underline">True</property>
 		      <property name="relief">GTK_RELIEF_NORMAL</property>
 		      <property name="focus_on_click">True</property>
@@ -16057,7 +16057,7 @@ Banner</property>
 		  <child>
 		    <widget class="GtkLabel" id="label334">
 		      <property name="visible">True</property>
-		      <property name="label" translatable="yes">Font style</property>
+		      <property name="label" translatable="yes">Font style:</property>
 		      <property name="use_underline">True</property>
 		      <property name="use_markup">False</property>
 		      <property name="justify">GTK_JUSTIFY_LEFT</property>