Fix empty articles for shell docs

I'm not sure I'm doing here everything right, so it's just my assumption:

The header I migrate from libview_private_headers to libview_headers are used in the documentation.
Also they do not have this inside:

#if !defined (XREADER_COMPILATION)
#error "This is a private header."
#endif

like other private header do (libview/ev-link-accessible.h) for example.

So if I'm wrong and the headers I move are really private then:
- they should have this "error "This is a private header." listed above as well
- they should be removed from xml to generate doc for shell

help/reference/shell/meson.build

@@ -20,7 +20,6 @@ gnome.gtkdoc(
         join_paths(meson.source_root(), 'shell'),
         join_paths(meson.source_root(), 'libmisc'),
     ],
-    ignore_headers: [libview_private_headers],
     dependencies: xreader_doc_deps,
     mkdb_args: ['--xml-mode', '--output-format=xml', '--name-space=ev'],
     c_args: '-DXREADER_COMPILATION',

libview/meson.build

@@ -1,23 +1,23 @@
 libview_private_headers = [
-    'ev-annotation-window.h',
     'ev-link-accessible.h',
-    'ev-loading-window.h',
-    'ev-page-cache.h',
-    'ev-pixbuf-cache.h',
     'ev-timeline.h',
     'ev-transition-animation.h',
     'ev-view-accessible.h',
-    'ev-view-cursor.h',
     'ev-view-private.h',
 ]
 
 libview_headers = [
+    'ev-annotation-window.h',
     'ev-document-model.h',
     'ev-jobs.h',
     'ev-job-scheduler.h',
+    'ev-loading-window.h',
+    'ev-page-cache.h',
+    'ev-pixbuf-cache.h',
     'ev-print-operation.h',
     'ev-stock-icons.h',
     'ev-view.h',
+    'ev-view-cursor.h',
     'ev-web-view.h',
     'ev-view-presentation.h',
 ]