[gtk/ebassi/gidocgen] docs: Tweak X11 section

[Matthias Clasen <matthiasc src gnome org>]

commit ecc4801ab85ff529ce62fdc6b9f1b39a31f84af7
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Feb 20 00:21:42 2021 -0500

    docs: Tweak X11 section
    
    Remove unsupported heading anchors.

 docs/reference/gtk/x11.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/docs/reference/gtk/x11.md b/docs/reference/gtk/x11.md
index 675e9e6061..2946747dee 100644
--- a/docs/reference/gtk/x11.md
+++ b/docs/reference/gtk/x11.md
@@ -8,7 +8,7 @@ To mix low-level Xlib routines into a GTK program, see
 [GDK X Window System interaction](#gdk-X-Window-System-Interaction)
 in the GDK manual.
 
-## X11-specific environment variables {#x11-envar}
+## X11-specific environment variables
 :
 The X11 GDK backend can be influenced with some additional environment variables.