[meld] ui.statusbar: Add some missed translatable strings and disambiguate one

[Kai Willadsen <kaiw src gnome org>]

commit 744de3622ee0ee059068c25367481c0cce2f9af5
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Mon Jan 21 05:56:39 2019 +1000

    ui.statusbar: Add some missed translatable strings and disambiguate one

 meld/resources/ui/statusbar-menu.ui | 8 ++++----
 meld/ui/statusbar.py                | 2 ++
 2 files changed, 6 insertions(+), 4 deletions(-)
---
diff --git a/meld/resources/ui/statusbar-menu.ui b/meld/resources/ui/statusbar-menu.ui
index ec9594ab..c8f32bba 100644
--- a/meld/resources/ui/statusbar-menu.ui
+++ b/meld/resources/ui/statusbar-menu.ui
@@ -2,19 +2,19 @@
 <interface>
   <menu id="statusbar-menu">
     <item>
-      <attribute name="label">Show line numbers</attribute>
+      <attribute name="label" translatable="yes">Show line numbers</attribute>
       <attribute name="action">show-line-numbers</attribute>
     </item>
     <item>
-      <attribute name="label">Show whitespace</attribute>
+      <attribute name="label" translatable="yes">Show whitespace</attribute>
       <attribute name="action">draw-spaces-bool</attribute>
     </item>
     <item>
-      <attribute name="label">Highlight current line</attribute>
+      <attribute name="label" translatable="yes">Highlight current line</attribute>
       <attribute name="action">highlight-current-line-local</attribute>
     </item>
     <item>
-      <attribute name="label">Text wrapping</attribute>
+      <attribute name="label" translatable="yes">Text wrapping</attribute>
       <attribute name="action">wrap-mode-bool</attribute>
     </item>
   </menu>
diff --git a/meld/ui/statusbar.py b/meld/ui/statusbar.py
index f8d0790b..a806d765 100644
--- a/meld/ui/statusbar.py
+++ b/meld/ui/statusbar.py
@@ -277,6 +277,8 @@ class MeldStatusBar(Gtk.Statusbar):
         pop.set_position(Gtk.PositionType.TOP)
 
         button = MeldStatusMenuButton()
+        # TRANSLATORS: This is the status bar label for a group of settings,
+        # such as text wrapping, show line numbers, whitespace, etc.
         button.set_label(_('Display'))
         button.set_popover(pop)
         button.show()