docs(watch): update docs to the correct param strings (#1645)

Fixes NODE-1272

lib/change_stream.js

@@ -13,7 +13,7 @@ var cursorOptionNames = ['maxAwaitTimeMS', 'collation', 'readPreference'];
  * @param {(Db|Collection)} changeDomain The collection against which to create the change stream
  * @param {Array} pipeline An array of {@link https://docs.mongodb.com/manual/reference/operator/aggregation-pipeline/|aggregation pipeline stages} through which to pass change stream documents
  * @param {object} [options=null] Optional settings
- * @param {string} [options.fullDocument=none] Allowed values: ‘none’, ‘lookup’. When set to ‘lookup’, the change stream will include both a delta describing the changes to the document, as well as a copy of the entire document that was changed from some time after the change occurred.
+ * @param {string} [options.fullDocument='default'] Allowed values: ‘default’, ‘updateLookup’. When set to ‘updateLookup’, the change stream will include both a delta describing the changes to the document, as well as a copy of the entire document that was changed from some time after the change occurred.
  * @param {number} [options.maxAwaitTimeMS] The maximum amount of time for the server to wait on new documents to satisfy a change stream query
  * @param {object} [options.resumeAfter=null] Specifies the logical starting point for the new change stream. This should be the _id field from a previously returned change stream document.
  * @param {number} [options.batchSize=null] The number of documents to return per batch. See {@link https://docs.mongodb.com/manual/reference/command/aggregate|aggregation documentation}.

lib/collection.js

@@ -2526,7 +2526,7 @@ define.classMethod('aggregate', { callback: true, promise: false });
  * @since 3.0.0
  * @param {Array} [pipeline=null] An array of {@link https://docs.mongodb.com/manual/reference/operator/aggregation-pipeline/|aggregation pipeline stages} through which to pass change stream documents. This allows for filtering (using $match) and manipulating the change stream documents.
  * @param {object} [options=null] Optional settings
- * @param {string} [options.fullDocument=none] Allowed values: ‘none’, ‘lookup’. When set to ‘lookup’, the change stream will include both a delta describing the changes to the document, as well as a copy of the entire document that was changed from some time after the change occurred.
+ * @param {string} [options.fullDocument='default'] Allowed values: ‘default’, ‘updateLookup’. When set to ‘updateLookup’, the change stream will include both a delta describing the changes to the document, as well as a copy of the entire document that was changed from some time after the change occurred.
  * @param {object} [options.resumeAfter=null] Specifies the logical starting point for the new change stream. This should be the _id field from a previously returned change stream document.
  * @param {number} [options.maxAwaitTimeMS] The maximum amount of time for the server to wait on new documents to satisfy a change stream query
  * @param {number} [options.batchSize=null] The number of documents to return per batch. See {@link https://docs.mongodb.com/manual/reference/command/aggregate|aggregation documentation}.