Add clarification on metrics parameter filter[hours_ago] (#1874)

Co-authored-by: ci.datadog-api-spec <[email protected]>
Co-authored-by: api-clients-generation-pipeline[bot] <54105614+api-clients-generation-pipeline[bot]@users.noreply.github.com> 0707019

datadog_api_client.v2.api.html

@@ -6229,7 +6229,7 @@ <h1 id="datadog-api-client-v2-api--page-root">datadog_api_client.v2.api<a class=
 <dd class="field-odd"><ul class="simple">
 <li><p><strong>metric_name</strong> (<em>str</em>) – The name of the metric.</p></li>
 <li><p><strong>filter_groups</strong> (<em>str</em><em>, </em><em>optional</em>) – Filtered tag keys that the metric is configured to query with.</p></li>
-<li><p><strong>filter_hours_ago</strong> (<em>int</em><em>, </em><em>optional</em>) – The number of hours of look back (from now) to estimate cardinality with.</p></li>
+<li><p><strong>filter_hours_ago</strong> (<em>int</em><em>, </em><em>optional</em>) – The number of hours of look back (from now) to estimate cardinality with. Estimates are based on historical data, and unspecified fields default to the minimum 49 hours.</p></li>
 <li><p><strong>filter_num_aggregations</strong> (<em>int</em><em>, </em><em>optional</em>) – The number of aggregations that a <code class="docutils literal notranslate"><span class="pre">count</span></code> , <code class="docutils literal notranslate"><span class="pre">rate</span></code> , or <code class="docutils literal notranslate"><span class="pre">gauge</span></code> metric is configured to use. Max number of aggregation combos is 9.</p></li>
 <li><p><strong>filter_pct</strong> (<em>bool</em><em>, </em><em>optional</em>) – A boolean, for distribution metrics only, to estimate cardinality if the metric includes additional percentile aggregators.</p></li>
 <li><p><strong>filter_timespan_h</strong> (<em>int</em><em>, </em><em>optional</em>) – A window, in hours, from the look back to estimate cardinality with.</p></li>