[libgxps] RELEASING: Update instructions to build the tarball

[Carlos Garcia Campos <carlosgc src gnome org>]

commit bec557d3826d778a27dacd52f41d78ee314be11e
Author: Carlos Garcia Campos <carlosgc gnome org>
Date:   Wed Aug 9 14:31:53 2017 +0200

    RELEASING: Update instructions to build the tarball
    
    With meson, API docs are not generated even when building with gtk-doc
    option enabled. Since we want to keep including the generated
    documentation in the tarball, we need to manually run the libgxps-doc
    target before the release one.

 RELEASING |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/RELEASING b/RELEASING
index 31aa0e6..af57686 100644
--- a/RELEASING
+++ b/RELEASING
@@ -40,9 +40,9 @@ Here are the steps to follow to create a new libgxps release:
         Adjust current, revision and age as described in the
         comments in the top level meson.build.
 
-4) Run "ninja release"
+4) Run "ninja libgxps-doc release"
 
-        Running "ninja release" generates the new tarball on the form of:
+        Running "ninja libgxps-doc release" generates the new tarball on the form of:
 
         libgxps-X.Y.Z.tar.xz