#278 Address RSVG library deprecated functions

[William Kendrick]

Our use of RSVG library needs to be update.

‘rsvg_handle_get_dimensions’ is deprecated: Use 'rsvg_handle_get_intrinsic_size_in_pixels'
‘rsvg_handle_close’ is deprecated: Use 'rsvg_handle_read_stream_sync'
‘rsvg_handle_render_cairo’ is deprecated: Use 'rsvg_handle_render_document'

[William Kendrick]

Dealt with ...get_dimensions and ...render_cairo. For rsvg_handle_close, see the notes in https://www.manpagez.com/html/rsvg-2.0/rsvg-2.0-2.52.1/RsvgHandle.php#rsvg-handle-close on how to rewrite things.

[William Kendrick]

In fact (per https://github.com/xfce-mirror/xfce4-xkb-plugin/commit/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() (https://gnome.pages.gitlab.gnome.org/librsvg/Rsvg-2.0/method.Handle.close.html)

So just commented _close() calls!