[gnome-shell-sass] theme: Use tabular figures where appropriate

[Florian Müllner <fmuellner src gnome org>]

commit ac33b4f22929aecd90bb1483aa3c1a886be7d665
Author: Ryan Hendrickson <ryan hendrickson alum mit edu>
Date:   Thu May 17 10:45:02 2018 -0400

    theme: Use tabular figures where appropriate
    
    In places where numbers appear in columns (like the calendar widget) or
    where changing numbers would result in labels jiggling around due to
    small width changes (like the clock), use the newly added
    font-feature-settings support to request tabular figures.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/34

 _common.scss | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/_common.scss b/_common.scss
index 433c13c..f1e6ae5 100644
--- a/_common.scss
+++ b/_common.scss
@@ -733,6 +733,7 @@ StScrollBar {
   transition-duration: 500ms;
   font-weight: bold;
   height: 1.86em;
+  font-feature-settings: "tnum";
 
   &.unlock-screen,
   &.login-screen,
@@ -958,6 +959,7 @@ StScrollBar {
       padding: 0.1em;
       margin: 2px;
       border-radius: 1.4em;
+      font-feature-settings: "tnum";
       &:hover,&:focus { background-color: lighten($bg_color,5%); }
       &:active,&:selected {
         color: lighten($selected_fg_color,5%);
@@ -1867,6 +1869,7 @@ StScrollBar {
 .screen-shield-clock-time {
   font-size: 72pt;
   text-shadow: 0px 2px 2px rgba(0,0,0,0.4);
+  font-feature-settings: "tnum";
 }
 
 .screen-shield-clock-date {