public void setNamespaceAllowList(Set<String> namespaceAllowList) {
            this.namespaceAllowList = namespaceAllowList;
        }
Sets a list of namespaces that can be referred to in metadata suppressions.

<p>Metadata suppressions that refer to namespaces outside of this list,
including "*", will be removed.

<p>This setting cannot be used in tandem with {@code namespaceDenyList}.

@param namespaceAllowList Namespaces to allow.
smithy-build/src/main/java/software/amazon/smithy/build/transforms/FilterSuppressions.java