fix(Guides): add optional datasetVersionId

Co-authored-by: Ellen Kraffmiller <[email protected]>

docs/useCases.md

@@ -67,7 +67,7 @@ _See [use case](../src/datasets/domain/useCases/GetDataset.ts)_ definition.
 
 The `datasetId` parameter can be a string, for persistent identifiers, or a number, for numeric identifiers.
 
-The `datasetVersionId` parameter can correspond to a numeric version identifier, as in the previous example, or a [DatasetNotNumberedVersion](../src/datasets/domain/models/DatasetNotNumberedVersion.ts) enum value. If not set, the default value is `DatasetNotNumberedVersion.LATEST`.
+The optional `datasetVersionId` parameter can correspond to a numeric version identifier, as in the previous example, or a [DatasetNotNumberedVersion](../src/datasets/domain/models/DatasetNotNumberedVersion.ts) enum value. If not set, the default value is `DatasetNotNumberedVersion.LATEST`.
 
 There is an optional third parameter called `includeDeaccessioned`, which indicates whether to consider deaccessioned versions or not in the dataset search. If not set, the default value is `false`.