FIX: Multiple values are multiple notch frequencies

Author: effigies

src/schema/objects/columns.yaml

@@ -302,9 +302,10 @@ notch:
   display_name: Notch frequencies
   description: |
     Frequencies used for the notch filter applied to the channel, in Hz.
-    If the low and high frequencies are supplied in addition to the center frequency,
-    they MAY take the form `[low, center, high]`, for example `[60, 120, 180]`.
-    If no notch filter applied, use `n/a`.
+    If notch filters are applied at multiple frequencies,
+    these frequencies MAY be specified as a list,
+    for example, `[60, 120, 180]`.
+    If no notch filter was applied, use `n/a`.
   type: string
 onset:
   name: onset