Synced changes with doc team sources.
Small correction to get-metric-statistics example
re-added lines from commit fb84aaf9bccdd009123ba3c4628f47a407672ea8
Fixed unwieldy description in s3/_concepts.rst and the related subcommand test.
Update example to quote entire Key value

The previous version was exposing a shorthand parsing bug that will be
fixed in the CLI.

cc @EronHennessey
Correct syntax for describe-volumes example
Fixed describe-reserved-instances with correct --filter syntax
Fix describe-vpc-peering-connection with correct filter syntax
Merge branch 'EronHennessey-doc_updates' into develop

* EronHennessey-doc_updates:
  Fix describe-vpc-peering-connection with correct filter syntax
  Fixed describe-reserved-instances with correct --filter syntax
  Correct syntax for describe-volumes example
  Update example to quote entire Key value
  Fixed unwieldy description in s3/_concepts.rst and the related subcommand test.
  re-added lines from commit fb84aaf9bccdd009123ba3c4628f47a407672ea8
  Small correction to get-metric-statistics example
  Synced changes with doc team sources.