Add subtext

.chloggen/tailsamplingprocessor-fixed-sampling-decision-metrics.yaml

@@ -15,7 +15,12 @@ issues: [37212]
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-subtext:
+subtext: |
+  As a result of this change non-zero values of `otelcol_processor_tail_sampling_sampling_trace_dropped_too_early`
+  and `otelcol_processor_tail_sampling_sampling_policy_evaluation_error_total` metrics will be lower.
+  Before this fix, errors got counted several times depending on the amount of traces being processed
+  that tick and where in the batch the error happened.
+  Zero values are unaffected.
 
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