[gedit] build: fix warning when building docs, about unused declarations

[Sébastien Wilmet <swilmet src gnome org>]

commit fa411a3abace76070736feaf77b1d62ea66de8ef
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Fri May 8 18:29:23 2020 +0200

    build: fix warning when building docs, about unused declarations

 gedit/meson.build | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gedit/meson.build b/gedit/meson.build
index 70d08a100..376c0cae6 100644
--- a/gedit/meson.build
+++ b/gedit/meson.build
@@ -155,6 +155,8 @@ libgedit_private_enum_types = gnome.mkenums_simple(
   sources: ['gedit-notebook.h'],
 )
 
+libgedit_private_headers += 'gedit-enum-types-private.h'
+
 subdir('resources')
 
 libgedit_sources += [