Add more internal headers for gtk-doc to ignore

This gives less bogus output in gio-unused.txt

docs/reference/gio/Makefile.am

@@ -18,7 +18,12 @@ CFILE_GLOB=$(top_srcdir)/gio/*.c
 
 # Headers to ignore
 IGNORE_HFILES=				\
+	asyncns.h			\
 	fam-helper.h			\
+	fen-data.h			\
+	fen-helper.h			\
+	fen-kernel.h			\
+	fen-node.h			\
 	gasynchelper.h			\
 	gcontenttypeprivate.h		\
 	gdummyfile.h			\
@@ -42,6 +47,7 @@ IGNORE_HFILES=				\
 	glocalfileoutputstream.h	\
 	glocalvfs.h			\
 	gnativevolumemonitor.h		\
+	gnetworkingprivate.h		\
 	gpollfilemonitor.h		\
 	gthreadedresolver.h		\
 	gunionvolumemonitor.h		\
@@ -66,6 +72,8 @@ IGNORE_HFILES=				\
 	xdgmimeint.h			\
 	xdgmimemagic.h			\
 	xdgmimeparent.h			\
+	xdgmimeicon.h			\
+	winhttp.h			\
 	$(NULL)
 
 # CFLAGS and LDFLAGS for compiling scan program. Only needed