docs: Clean up the unused symbols for Cogl

Gtk-doc is reporting a lot of false positives in the unused text file,
mostly because of new private files that have been added to Cogl but not
to the gtk-doc ignore list for the Cogl API reference.

Once the false positives have been removed we have a couple of really
missing symbols that should be added to the cogl-sections.txt file.

doc/reference/cogl/Makefile.am

@@ -53,30 +53,36 @@ CFILE_GLOB=\
 # Header files to ignore when scanning.
 # e.g. IGNORE_HFILES=gtkdebug.h gtkintl.h
 IGNORE_HFILES=\
-	cogl-bitmap-private.h \
-	cogl-blend-string.h \
-	cogl-clip-stack.h \
-	cogl-context.h \
-	cogl-debug.h \
-	cogl-defines.h \
-	cogl-deprecated.h \
-	cogl-draw-buffer-private.h \
-	cogl-feature-private.h \
-	cogl-handle.h \
-	cogl-internal.h \
-	cogl-journal-private.h \
-	cogl-material-private.h \
-	cogl-matrix-mesa.h \
-	cogl-matrix-private.h \
-	cogl-matrix-stack.h \
-	cogl-spans.h \
-	cogl-primitives.h \
-	cogl-texture-2d-sliced-private.h \
-	cogl-texture-driver.h \
-	cogl-texture-private.h \
-	cogl-util.h \
-	cogl-vertex-buffer-private.h \
-	driver \
+	cogl-atlas-texture-private.h 		\
+	cogl-bitmap-private.h 			\
+	cogl-blend-string.h 			\
+	cogl-buffer-private.h 			\
+	cogl-clip-stack.h 			\
+	cogl-context.h 				\
+	cogl-debug.h 				\
+	cogl-defines.h 				\
+	cogl-deprecated.h 			\
+	cogl-draw-buffer-private.h 		\
+	cogl-feature-private.h 			\
+	cogl-framebuffer-private.h 		\
+	cogl-handle.h 				\
+	cogl-internal.h 			\
+	cogl-journal-private.h 			\
+	cogl-material-private.h 		\
+	cogl-matrix-mesa.h 			\
+	cogl-matrix-private.h 			\
+	cogl-matrix-stack.h 			\
+	cogl-spans.h 				\
+	cogl-pixel-buffer-private.h		\
+	cogl-primitives.h 			\
+	cogl-sub-texture-private.h		\
+	cogl-texture-2d-private.h		\
+	cogl-texture-2d-sliced-private.h 	\
+	cogl-texture-driver.h 			\
+	cogl-texture-private.h 			\
+	cogl-util.h 				\
+	cogl-vertex-buffer-private.h 		\
+	driver 					\
 	winsys
 
 EXTRA_HFILES=

doc/reference/cogl/cogl-sections.txt

@@ -424,6 +424,7 @@ cogl_matrix_get_inverse
 <FILE>cogl-material</FILE>
 <TITLE>Materials</TITLE>
 cogl_material_new
+cogl_material_copy
 cogl_material_ref
 cogl_material_unref
 cogl_is_material
@@ -456,6 +457,7 @@ cogl_material_get_layers
 cogl_material_get_n_layers
 CoglMaterialFilter
 cogl_material_set_layer_filters
+CoglMaterialLayerType
 cogl_material_layer_get_type
 cogl_material_layer_get_texture
 cogl_material_layer_get_min_filter
@@ -484,9 +486,14 @@ cogl_buffer_set_data
 <SUBSECTION>
 cogl_pixel_buffer_new
 cogl_pixel_buffer_new_for_size
+cogl_pixel_buffer_set_region
 cogl_is_pixel_buffer
 
 <SUBSECTION>
 cogl_texture_new_from_buffer
 
+<SUBSECTION Private>
+cogl_buffer_access_get_type
+cogl_buffer_update_hint_get_type
+cogl_buffer_usage_hint_get_type
 </SECTION>