[mutter] core/display: Remove obsolete typedef

[Robert Mader <rmader src gnome org>]

commit c1c061140f743d8c6745479261f339fd2cecc115
Author: Florian Müllner <fmuellner gnome org>
Date:   Mon Aug 31 19:24:50 2020 +0200

    core/display: Remove obsolete typedef
    
    The corresponding type was replaced in 2001.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1425

 src/core/display-private.h | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/src/core/display-private.h b/src/core/display-private.h
index 251e9e2a88..7d70a8301d 100644
--- a/src/core/display-private.h
+++ b/src/core/display-private.h
@@ -48,7 +48,6 @@
 
 typedef struct _MetaBell       MetaBell;
 typedef struct _MetaStack      MetaStack;
-typedef struct _MetaUISlave    MetaUISlave;
 
 typedef struct MetaEdgeResistanceData MetaEdgeResistanceData;