[gtksourceview] build: update gtk-doc build

[Christian Hergert <chergert src gnome org>]

commit ce0ffd8f8cb0a903be94a5b8b5837afb8d2576d9
Author: Christian Hergert <chergert redhat com>
Date:   Tue Sep 22 18:24:01 2020 -0700

    build: update gtk-doc build

 docs/reference/meson.build | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)
---
diff --git a/docs/reference/meson.build b/docs/reference/meson.build
index 8fe0ecf3..b491ecc9 100644
--- a/docs/reference/meson.build
+++ b/docs/reference/meson.build
@@ -7,28 +7,30 @@ gtk_docpath = join_paths(gtk_prefix, 'share', 'gtk-doc', 'html')
 reference_private_h = [
   'config.h',
   'gtksource.h',
+  'gtksourceassistant-private.h',
+  'gtksourceassistantchild-private.h',
+  'gtksourcebindinggroup-private.h',
   'gtksourcebuffer-private.h',
   'gtksourcebufferinputstream-private.h',
   'gtksourcebufferinternal-private.h',
   'gtksourcebufferoutputstream-private.h',
   'gtksourcecompletion-private.h',
-  'gtksourcecompletioncontainer-private.h',
+  'gtksourcecompletioncell-private.h',
   'gtksourcecompletioncontext-private.h',
   'gtksourcecompletioninfo-private.h',
-  'gtksourcecompletionmodel-private.h',
-  'gtksourcecompletionsnippetsproposal-private.h',
-  'gtksourcecompletionwordsbuffer-private.h',
-  'gtksourcecompletionwordslibrary-private.h',
-  'gtksourcecompletionwordsproposal-private.h',
-  'gtksourcecompletionwordsutils-private.h',
+  'gtksourcecompletionlist-private.h',
+  'gtksourcecompletionlistbox-private.h',
+  'gtksourcecompletionlistboxrow-private.h',
   'gtksourcecontextengine-private.h',
   'gtksourceencoding-private.h',
   'gtksourceengine-private.h',
   'gtksourcefile-private.h',
   'gtksourcegutter-private.h',
+  'gtksourcegutterlines-private.h',
   'gtksourcegutterrenderer-private.h',
   'gtksourcegutterrendererlines-private.h',
   'gtksourcegutterrenderermarks-private.h',
+  'gtksourceinformative-private.h',
   'gtksourceiter-private.h',
   'gtksourcelanguage-private.h',
   'gtksourcelanguagemanager-private.h',
@@ -36,21 +38,32 @@ reference_private_h = [
   'gtksourcepixbufhelper-private.h',
   'gtksourceregex-private.h',
   'gtksourcesearchcontext-private.h',
+  'gtksourcesignalgroup-private.h',
   'gtksourcesnippet-private.h',
   'gtksourcesnippetbundle-private.h',
+  'gtksourcesnippetchunk-private.h',
   'gtksourcesnippetcontext-private.h',
   'gtksourcesnippetmanager-private.h',
+  'gtksourcespacedrawer-private.h',
   'gtksourcestyle-private.h',
   'gtksourcestylescheme-private.h',
   'gtksourcestyleschememanager-private.h',
+  'gtksourcetrace.h',
   'gtksourcetypes-private.h',
   'gtksourceutils-private.h',
+  'gtksourceview-private.h',
+  'gtksourcecompletionwordsbuffer-private.h',
+  'gtksourcecompletionwordslibrary-private.h',
+  'gtksourcecompletionwordsproposal-private.h',
+  'gtksourcecompletionwordsutils-private.h',
+  'gtksourcecompletionsnippetsproposal-private.h',
   'quarkset-inline.h',
 ]
 
 reference_content_files = files([
   'lang-tutorial.xml',
   'porting-guide-3-to-4.xml',
+  'porting-guide-4-to-5.xml',
 ])
 
 reference_sources = [