Don't call rsvg_handle_close(); it's deprecated

Borrowing from 825fa1c,

- rsvg_handle_close() is deprecated from librsvg 2.46, together with
  rsvg_handle_write()
- rsvg_handle_close() is only needed to be called after
  rsvg_handle_write()
- rsvg_handle_close() isn't needed to be called after
  rsvg_handle_new_from_file() [1]

1: https://gnome.pages.gitlab.gnome.org/librsvg/Rsvg-2.0/method.Handle.close.html

Shrug!

Closes https://sourceforge.net/p/tuxpaint/bugs/278/

docs/CHANGES.txt

@@ -80,6 +80,11 @@ https://tuxpaint.org/
       (https://sourceforge.net/p/tuxpaint/tuxpaint/merge-requests/19/)
       Will Thompson <https://sourceforge.net/u/wjjjjt/profile/>
 
+    * Don't call rsvg_handle_close(); it's deprecated, and not necessary;
+      (see https://gnome.pages.gitlab.gnome.org/librsvg/Rsvg-2.0/method.Handle.close.html;
+      h/t https://github.com/xfce-mirror/xfce4-xkb-plugin/commit/825fa1c
+      Bill Kendrick <bill@newbreedsoftware.com>
+
   * Documentation updates:
     ----------------------
     * Troubleshooting Guide (TROUBLESHOOTING.txt) updated regarding