Fix the encoding of noise.h

Convert what appears to be a EUC-JP right angle bracket "〉" to a plain
ASCII greater than sign ">". This fixes an error when using Visual C++
with the /utf-8 flag.

src/spandsp/noise.h

@@ -69,7 +69,7 @@ Freq (Hz)  Spectral     Bandwidth       Total power in
 6300        -1.3        31.7            30.4
 8000        -6.6        32.7            26.0
 
-The tolerance for each 1/3rd octave band is ¡Ó3dB.
+The tolerance for each 1/3rd octave band is > 3dB.
 
 \section awgn_page_sec_2 How does it work?
 The central limit theorem says if you add a few random numbers together,