fix(lambda-event-sources): incorrect documented defaults for stream t…

…ypes (aws#14562)

The defaults documented for `maxRecordAge` and `retryAttempts`
properties for event sources that are 'stream' type were documented
incorrectly.

The implementation falls back to the defaults provided by
CloudFormation.

fixes aws#13908


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-lambda-event-sources/lib/stream.ts

@@ -41,7 +41,7 @@ export interface StreamEventSourceProps {
    * * Minimum value of 60 seconds
    * * Maximum value of 7 days
    *
-   * @default Duration.days(7)
+   * @default - the retention period configured on the stream
    */
   readonly maxRecordAge?: Duration;
 
@@ -51,7 +51,7 @@ export interface StreamEventSourceProps {
    * * Minimum value of 0
    * * Maximum value of 10000
    *
-   * @default 10000
+   * @default - retry until the record expires
    */
   readonly retryAttempts?: number;