Filter: add "source" to option 5

libraries/Filter/HarmonicNotchFilter.cpp

@@ -125,7 +125,7 @@ const AP_Param::GroupInfo HarmonicNotchFilterParams::var_info[] = {
     // @Param: OPTS
     // @DisplayName: Harmonic Notch Filter options
     // @Description: Harmonic Notch Filter options. Triple and double-notches can provide deeper attenuation across a wider bandwidth with reduced latency than single notches and are suitable for larger aircraft. Multi-Source attaches a harmonic notch to each detected noise frequency instead of simply being multiples of the base frequency, in the case of FFT it will attach notches to each of three detected noise peaks, in the case of ESC it will attach notches to each of four motor RPM values. Loop rate update changes the notch center frequency at the scheduler loop rate rather than at the default of 200Hz. If both double and triple notches are specified only double notches will take effect.
-    // @Bitmask: 0:Double notch,1:Multi-Source,2:Update at loop rate,3:EnableOnAllIMUs,4:Triple notch, 5:Use min freq on RPM failure
+    // @Bitmask: 0:Double notch,1:Multi-Source,2:Update at loop rate,3:EnableOnAllIMUs,4:Triple notch, 5:Use min freq on RPM source failure
     // @User: Advanced
     // @RebootRequired: True
     AP_GROUPINFO("OPTS", 8, HarmonicNotchFilterParams, _options, 0),