[gtk] docs: Ignore more private headers

[Matthias Clasen <matthiasc src gnome org>]

commit 21a032b78311d1a3c4a0139f523f8bda5b2ba007
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Dec 12 17:58:23 2019 -0500

    docs: Ignore more private headers

 docs/reference/gtk/meson.build | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/docs/reference/gtk/meson.build b/docs/reference/gtk/meson.build
index 60194f208a..6f5224ff58 100644
--- a/docs/reference/gtk/meson.build
+++ b/docs/reference/gtk/meson.build
@@ -178,8 +178,10 @@ private_headers = [
   'gtktextchildprivate.h',
   'gtktextdisplayprivate.h',
   'gtktexthandleprivate.h',
+  'gtktexthistoryprivate.h',
   'gtktextiterprivate.h',
   'gtktextlayoutprivate.h',
+  'gtktextlinedisplaycacheprivate.h',
   'gtktextmarkprivate.h',
   'gtktexttagprivate.h',
   'gtktextviewprivate.h',