better documentation for exclusions

[jlongman]

A suggestion to add better docs for exclusion. I got it working but not sure if I understand the full permutations. this worked for me (in drawio, note #47):

 -e AWS::S3::BucketPolicy -e AWS::IAM::Policy -e AWS::Lambda::Permission -e Custom::S3AutoDeleteObjects

(It wasn't clear if I could use commas?)

The example also helps clarify the way to specify a Type.

Also, I can create a separate ticket, but maybe it's documentation: Can I filter element names?

As mentioned in #47, this is because the cdk introduces some custom resources which are useful but not core to the expression of my diagram, but of course the Custom Types are filterable but the AWS:Lambda:Function types overlap "useful" ones.