add noqa comment to long line
@@ -24,7 +24,7 @@ described in [5]_.
.. [3] http://fourier.eng.hmc.edu/e161/lectures/dct/node2.html
-.. [4] https://dsp.stackexchange.com/questions/2807/fast-cosine-transform-via-fft
+.. [4] https://dsp.stackexchange.com/questions/2807/fast-cosine-transform-via-fft # noqa
.. [5] X. Shao, S. G. Johnson. Type-II/III DCT/DST algorithms with reduced
number of arithmetic operations, Signal Processing, Volume 88, Issue 6,
