docs-rst: replace the selection.png by a SVG image

bitmap images don't scale too well. So, replace it by a SVG
image, written in inkscape. I'm using the 2009's temporary
logo.svg image from 8032b526d1 ("linux.conf.au 2009: Tuz"),
with a Tasmanian Devil wearing a tux mask.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/media/uapi/v4l/selection-api-003.rst

@@ -7,8 +7,8 @@ Selection targets
 
 .. _sel-targets-capture:
 
-.. figure::  selection.png
-    :alt:    selection.png
+.. figure::  selection.*
+    :alt:    selection.pdf / selection.svg
     :align:  center
 
     Cropping and composing targets