[gtk/gtk-3-24] Don't forget to dist gtktexttagprivate.h

[Matthias Clasen <matthiasc src gnome org>]

commit a923ee9b876ea700b6b5db4bf951f39a147c1ef5
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Mar 27 16:50:15 2020 -0400

    Don't forget to dist gtktexttagprivate.h

 gtk/Makefile.am | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gtk/Makefile.am b/gtk/Makefile.am
index eaca4737dc..463b3a40b1 100644
--- a/gtk/Makefile.am
+++ b/gtk/Makefile.am
@@ -583,6 +583,7 @@ gtk_private_h_sources =             \
        gtktextmarkprivate.h    \
        gtktextsegment.h        \
        gtktexttagprivate.h     \
+       gtktexttagtableprivate.h        \
        gtktexttypes.h          \
        gtktextutil.h           \
        gtktrashmonitor.h       \