Mark MetricReader cardinality limit as stable (#4245)

specification/metrics/sdk.md

@@ -1231,7 +1231,7 @@ SHOULD be provided:
 * The `exporter` to use, which is a `MetricExporter` instance.
 * The default output `aggregation` (optional), a function of instrument kind. This function SHOULD be obtained from the `exporter`. If not configured, the [default aggregation](#default-aggregation) SHOULD be used.
 * The output `temporality` (optional), a function of instrument kind. This function SHOULD be obtained from the `exporter`. If not configured, the Cumulative temporality SHOULD be used.
-* **Status**: [Development](../document-status.md) - The default aggregation cardinality limit to use, a function of instrument kind.  If not configured, a default value of 2000 SHOULD be used.
+* The default aggregation [cardinality limit](#cardinality-limits) (optional) to use, a function of instrument kind.  If not configured, a default value of 2000 SHOULD be used.
 * **Status**: [Development](../document-status.md) - The [MetricFilter](#metricfilter) to apply to metrics and attributes during `MetricReader#Collect`.
 * Zero of more [MetricProducer](#metricproducer)s (optional) to collect metrics from in addition to metrics from the SDK.