Fix type in `oms` noise

lisainstrument/noises.py

@@ -210,11 +210,11 @@ def oms(fs, size, asd, fknee):
 
     The power spectral density in displacement is given by
 
-        S_bl(f) [m] = asd^2 [ 1 + (fknee / f)^4 ].
+        S_oms(f) [m] = asd^2 [ 1 + (fknee / f)^4 ].
 
     Multiplying by (2π f / c)^2 to express it as fractional frequency deviations,
 
-        S_bl(f) [ffd] = (2π asd / c)^2 [ f^2 + (fknee^4 / f^2) ]
+        S_oms(f) [ffd] = (2π asd / c)^2 [ f^2 + (fknee^4 / f^2) ]
                       = (2π asd / c)^2 f^2 + (2π asd fknee^2 / c)^2 f^(-2)
 
     Note that the level of this noise depends on the interferometer and the type of beatnote.