Add :expires_in Details for Aws::S3::Presigner
Add :expires_in Details for Aws::S3::Presigner

GitHub issues/PRs #927 #983 and #1442 refer to this limit, so adding an
explanatory note to the documentation.

hamadata/aws-sdk-ruby,llooker/aws-sdk-ruby,hamadata/aws-sdk-ruby,llooker/aws-sdk-ruby,cjyclaire/aws-sdk-ruby,cjyclaire/aws-sdk-ruby,cjyclaire/aws-sdk-ruby,hamadata/aws-sdk-ruby,aws/aws-sdk-ruby,aws/aws-sdk-ruby,aws/aws-sdk-ruby,llooker/aws-sdk-ruby