fixed bug in example code

doc/guide.rst

@@ -58,7 +58,7 @@ The function ``galbally_iqm_features::compute_quality_features()`` returns a 1D
    >>> video4d = bob.io.video.reader(video_file) # doctest: +SKIP
    >>> rgb_frame = video4d[0]
    >>> print(rgb_frame.shape)
-   [3, 480, 720]
+   (3, 480, 720)
    >>> gf_set = iqm.compute_quality_features(rgb_frame)
    >>> print(len(gf_set))
    18