GH-39416: [GLib][Docs] Fixed Broken Link in README Content (#39896)

### Rationale for this change

### What changes are included in this PR?
 Fixed Broken Link in README Content 

### Are these changes tested?
Yes

### Are there any user-facing changes?
Yes

* Closes: #39416

Lead-authored-by: Divyansh200102 <divyanshkhatri200102@gmail.com>
Co-authored-by: Divyansh200102 <146909065+Divyansh200102@users.noreply.github.com>
Co-authored-by: Sutou Kouhei <kou@cozmixng.org>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>

c_glib/README.md

@@ -101,7 +101,7 @@ $ sudo meson install -C c_glib.build
 You need to install Arrow C++ before you install Arrow GLib. See Arrow
 C++ document about how to install Arrow C++.
 
-You need [GTK-Doc](https://www.gtk.org/gtk-doc/) and
+You need [GTK-Doc](https://gitlab.gnome.org/GNOME/gtk-doc) and
 [GObject Introspection](https://wiki.gnome.org/Projects/GObjectIntrospection)
 to build Arrow GLib. You can install them by the followings: