[gnome-tweaks] extensions: Use dim-label for descriptions instead of hardcoded color

[Jeremy Bicha <jbicha src gnome org>]

commit 6a9b34a3fb17c81f31c07189af8dff85cd945674
Author: Jeremy Bicha <jbicha ubuntu com>
Date:   Thu Sep 27 10:02:41 2018 -0400

    extensions: Use dim-label for descriptions instead of hardcoded color
    
    This allows themes to set the appropriate color and matches
    what we already do elsewhere in Tweaks.
    
    Closes: https://gitlab.gnome.org/GNOME/gnome-tweaks/issues/168

 gtweak/tweaks/tweak_group_shell_extensions.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/gtweak/tweaks/tweak_group_shell_extensions.py b/gtweak/tweaks/tweak_group_shell_extensions.py
index 19e059a..47854a7 100644
--- a/gtweak/tweaks/tweak_group_shell_extensions.py
+++ b/gtweak/tweaks/tweak_group_shell_extensions.py
@@ -99,7 +99,8 @@ class _ShellExtensionTweak(Gtk.ListBoxRow, Tweak):
         lbl_name.set_markup("<span size='medium'><b>"+name_markup+"</b></span>")
         lbl_desc = _ExtensionDescriptionLabel(xalign=0.0, yalign=0.0, wrap=True, lines=2)
         desc = GLib.markup_escape_text(ext["description"].lower().capitalize().split('\n')[0])
-        lbl_desc.set_markup("<span foreground='#A19C9C' size='small'>"+desc+"</span>")
+        lbl_desc.set_markup("<span size='small'>"+desc+"</span>")
+        lbl_desc.get_style_context().add_class("dim-label")
         lbl_desc.props.ellipsize = Pango.EllipsizeMode.END
 
         vbox.pack_start(lbl_name, False, False, 0)