add comment abount fix(dotnet#60752)

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Metrics/AggregationManager.cs

@@ -302,6 +302,7 @@ private void RemoveInstrumentState(Instrument instrument, InstrumentState state)
                 {
                     lock (this)
                     {
+                        // checking currentHistograms first because avoiding unexpected increment of TimeSeries count.
                         return (!CheckHistogramAllowed() || !CheckTimeSeriesAllowed()) ?
                             null :
                             new ExponentialHistogramAggregator(s_defaultHistogramConfig);