[gnome-latex] BottomPanel: use tepl_utils_create_close_button()

[Sébastien Wilmet <swilmet src gnome org>]

commit 0196f5caf7e23806cde0d2bb20f4024383ec5014
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun Apr 19 22:33:23 2020 +0200

    BottomPanel: use tepl_utils_create_close_button()

 src/bottom_panel.vala | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
---
diff --git a/src/bottom_panel.vala b/src/bottom_panel.vala
index f7c4345..2881cb9 100644
--- a/src/bottom_panel.vala
+++ b/src/bottom_panel.vala
@@ -47,11 +47,8 @@ public class BottomPanel : Grid
 
     private Button get_close_button ()
     {
-        Button close_button = new Button ();
-        close_button.relief = ReliefStyle.NONE;
-        close_button.focus_on_click = false;
+        Button close_button = Tepl.utils_create_close_button () as Button;
         close_button.tooltip_text = _("Hide panel");
-        close_button.add (new Image.from_icon_name ("window-close", IconSize.MENU));
         close_button.clicked.connect (() => this.hide ());
 
         return close_button;