Rename hb-*private.hh to hb-*.hh

Sorry for the noise, downstream custom builders.  Please adjust.

src/hb-aat-layout.cc

diff --git a/src/hb-aat-layout.cc b/src/hb-aat-layout.cc
index fc706d6..24ec53b 100644
--- a/src/hb-aat-layout.cc
+++ b/src/hb-aat-layout.cc
@@ -24,12 +24,12 @@
  * Google Author(s): Behdad Esfahbod
  */
 
-#include "hb-open-type-private.hh"
+#include "hb-open-type.hh"
 
-#include "hb-ot-layout-private.hh"
-#include "hb-ot-layout-gsubgpos-private.hh"
+#include "hb-ot-layout.hh"
+#include "hb-ot-layout-gsubgpos.hh"
 
-#include "hb-aat-layout-private.hh"
+#include "hb-aat-layout.hh"
 #include "hb-aat-layout-ankr-table.hh"
 #include "hb-aat-layout-bsln-table.hh" // Just so we compile it; unused otherwise.
 #include "hb-aat-layout-feat-table.hh" // Just so we compile it; unused otherwise.