[gedit-plugins/colorshemer] Underline was deprecated in GtkSourceView 4

[Jordi Mas <jmas src gnome org>]

commit 316ac38cba01adc45e05285d7fde58490c80a4e5
Author: Jordi Mas <jmas softcatala org>
Date:   Sun May 5 23:40:05 2019 +0200

    Underline was deprecated in GtkSourceView 4

 plugins/colorschemer/schemer/schemer.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/plugins/colorschemer/schemer/schemer.py b/plugins/colorschemer/schemer/schemer.py
index 5993a7d..1ab18dc 100644
--- a/plugins/colorschemer/schemer/schemer.py
+++ b/plugins/colorschemer/schemer/schemer.py
@@ -24,7 +24,7 @@ import collections
 import tempfile
 from xml.etree import ElementTree as ET
 
-from gi.repository import Gtk, GdkPixbuf, Gdk, GtkSource, Gio, GLib
+from gi.repository import Gtk, GdkPixbuf, Gdk, GtkSource, Gio, GLib, Pango
 
 from .languages import samples
 
@@ -57,7 +57,7 @@ class Props:
     self.foreground = gtkStyle.props.foreground
     self.italic = gtkStyle.props.italic
     self.bold = gtkStyle.props.bold
-    self.underline = gtkStyle.props.underline
+    self.underline = gtkStyle.props.pango_underline == Pango.Underline.NONE
     self.strikethrough = gtkStyle.props.strikethrough
     
     # here we make sure every color starts with a hash