icons: Add stop-symbolic

This is a smaller version of the pre-installed
media-playback-stop-symbolic. It will be used for the screen recording
indicator.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2163>

data/gnome-shell-icons.gresource.xml

@@ -26,6 +26,7 @@
     <file>scalable/status/no-notifications-symbolic.svg</file>
     <file>scalable/status/screen-privacy-disabled-symbolic.svg</file>
     <file>scalable/status/screen-privacy-symbolic.svg</file>
+    <file>scalable/status/stop-symbolic.svg</file>
   </gresource>
 </gresources>
 

data/icons/scalable/status/stop-symbolic.svg

@@ -0,0 +1,2 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" height="16px" viewBox="0 0 16 16" width="16px"><path d="m 4 4 h 8 v 8 h -8 z m 0 0" fill="#2e3436"/></svg>