[gnome-builder] editor: add tooltip text

[Christian Hergert <chergert src gnome org>]

commit db2e08fac30e7cd04813523017d51ad305bd17e0
Author: Christian Hergert <chergert redhat com>
Date:   Tue Jul 4 18:50:28 2017 -0700

    editor: add tooltip text
    
    Eventually we'll want to use an IdeShortcutLabel for this which
    can get the appropriate shortcut from the active
    DzlShortcutTheme.

 libide/editor/ide-editor-workbench-addin.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/libide/editor/ide-editor-workbench-addin.c b/libide/editor/ide-editor-workbench-addin.c
index fde7251..d94d3cf 100644
--- a/libide/editor/ide-editor-workbench-addin.c
+++ b/libide/editor/ide-editor-workbench-addin.c
@@ -18,6 +18,7 @@
 
 #define G_LOG_DOMAIN "ide-editor-workbench-addin"
 
+#include <glib/gi18n.h>
 #include <gtksourceview/gtksource.h>
 #include <string.h>
 
@@ -160,6 +161,7 @@ ide_editor_workbench_addin_add_buttons (IdeEditorWorkbenchAddin *self,
   button = g_object_new (GTK_TYPE_TOGGLE_BUTTON,
                          "action-name", "dockbin.left-visible",
                          "focus-on-click", FALSE,
+                         "tooltip-text", _("Toggle navigation panel"),
                          "child", g_object_new (GTK_TYPE_IMAGE,
                                                 "icon-name", "panel-left-pane-symbolic",
                                                 "margin-start", 12,
@@ -173,6 +175,7 @@ ide_editor_workbench_addin_add_buttons (IdeEditorWorkbenchAddin *self,
   button = g_object_new (GTK_TYPE_TOGGLE_BUTTON,
                          "action-name", "dockbin.bottom-visible",
                          "focus-on-click", FALSE,
+                         "tooltip-text", _("Toggle utilities panel"),
                          "child", g_object_new (GTK_TYPE_IMAGE,
                                                 "icon-name", "panel-bottom-pane-symbolic",
                                                 "margin-start", 12,