[gnome-text-editor] css: fix border next to source map

[Christian Hergert <chergert src gnome org>]

commit bf8c0c249f06a0be69e65aed3b786ba02a9f999e
Author: Christian Hergert <chergert redhat com>
Date:   Mon Sep 6 17:35:49 2021 -0700

    css: fix border next to source map

 src/TextEditor.css | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/TextEditor.css b/src/TextEditor.css
index c6d88d3..3d63379 100644
--- a/src/TextEditor.css
+++ b/src/TextEditor.css
@@ -104,8 +104,8 @@
 }
 
 textview.source-map:dir(ltr) {
-  border-left: 1px solid alpha(@borders,.3);
+  border-left: 1px solid @borders;
 }
 textview.source-map:dir(rtl) {
-  border-right: 1px solid alpha(@borders,.3);
+  border-right: 1px solid @borders;
 }