[gtksourceview] css: use modern GTK 4.5+ line-height

[Christian Hergert <chergert src gnome org>]

commit 31bd4eb742f012c37e03e490399d8a07d6f6b963
Author: Christian Hergert <chergert redhat com>
Date:   Wed Feb 2 13:28:01 2022 -0800

    css: use modern GTK 4.5+ line-height

 gtksourceview/GtkSourceView.css | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtksourceview/GtkSourceView.css b/gtksourceview/GtkSourceView.css
index 2923c58d..e049364c 100644
--- a/gtksourceview/GtkSourceView.css
+++ b/gtksourceview/GtkSourceView.css
@@ -169,5 +169,5 @@ GtkSourceStyleSchemePreview.selected image {
 
 textview.GtkSourceMap {
   font-size: 1.75pt;
-  /* Requires GTK 4.6: line-height: 4px; */
+  line-height: 4px;
 }