[gtranslator/font-size] Add font label in preferences editor

[Daniel Garcia Moreno <danigm src gnome org>]

commit d19f786975c258a6e4390a6e3bd88f30ad786152
Author: Daniel García Moreno <dani danigm net>
Date:   Thu Sep 10 12:08:48 2020 +0200

    Add font label in preferences editor
    
    See https://gitlab.gnome.org/GNOME/gtranslator/-/issues/120

 src/gtr-preferences-dialog.ui | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)
---
diff --git a/src/gtr-preferences-dialog.ui b/src/gtr-preferences-dialog.ui
index d8211fe8..79b6fc0b 100644
--- a/src/gtr-preferences-dialog.ui
+++ b/src/gtr-preferences-dialog.ui
@@ -363,9 +363,36 @@
                               </packing>
                             </child>
                             <child>
-                              <object class="GtkFontButton" id="font_button">
+                              <object class="GtkBox">
                                 <property name="visible">True</property>
-                                <property name="can_focus">True</property>
+                                <property name="can_focus">False</property>
+                                <property name="orientation">horizontal</property>
+                                <property name="spacing">6</property>
+                                <child>
+                                  <object class="GtkLabel">
+                                    <property name="visible">True</property>
+                                    <property name="can_focus">False</property>
+                                    <property name="xalign">0</property>
+                                    <property name="label" translatable="yes">Font:</property>
+                                  </object>
+                                  <packing>
+                                    <property name="expand">False</property>
+                                    <property name="fill">False</property>
+                                    <property name="position">0</property>
+                                  </packing>
+                                </child>
+                                <child>
+                                  <object class="GtkFontButton" id="font_button">
+                                    <property name="visible">True</property>
+                                    <property name="can_focus">True</property>
+                                    <property name="title" translatable="yes">Choose the editor 
font</property>
+                                  </object>
+                                  <packing>
+                                    <property name="expand">False</property>
+                                    <property name="fill">False</property>
+                                    <property name="position">1</property>
+                                  </packing>
+                                </child>
                               </object>
                               <packing>
                                 <property name="expand">False</property>