[exporter/datadog] Update documentation

exporter/datadogexporter/example/config.yaml

@@ -72,6 +72,7 @@ exporters:
     #
     # metrics:
       ## @param send_monotonic_counter - boolean - optional - default: true
+      ## Deprecated: [v0.48.0] Use `metrics::sums::cumulative_monotonic_mode` instead.
       ## Whether to report monotonic metrics as counters or gauges (raw value).
       ## See https://docs.datadoghq.com/integrations/guide/prometheus-metrics/#counter
       ## for further details
@@ -118,6 +119,16 @@ exporters:
         ## Whether to report sum and count as separate histogram metrics.
         #
         # send_count_sum_metrics: false
+
+      ## @param sums - custom object - optional
+      ## Sums specific configuration.
+        ## @param cumulative_monotonic_mode - string - optional - default: to_delta
+        ## How to report cumulative monotonic sums. Valid values are:
+        ##
+        ## - `to_delta` to calculate delta for sum in the client side and report as Datadog counts.
+        ## - `raw_value` to report the raw value as a Datadog gauge.
+        #
+        # cumulative_monotonic_mode: to_delta
 
     ## @param traces - custom object - optional
     ## Trace exporter specific configuration.