[Storage] Fix BlobType description in help of Set-AzStorageBlobContent

[blueww]

Description

This PR is to add a sample script for Set ACL recursive.
Per before discussion with @dingmeng-xue , we can add this with a Reame.md file to point out which samples are included.

I don't add a changelog here, since the feature is just added with changelog in PR #13188, and the sample change should be a part of the feature.

The sample change won't impact the build and release of the coming Azure PSH release, so please help to merge it.

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate ChangeLog.md file(s) has been updated:
  • For any service, the ChangeLog.md file can be found at src/{{SERVICE}}/{{SERVICE}}/ChangeLog.md
  • A snippet outlining the change(s) made in the PR should be written under the ## Upcoming Release header -- no new version header should be added
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
  • a cmdlet design review was approved for the changes in this repository (Microsoft internal only)
  • the markdown help files have been regenerated using the commands listed here

[isra-fel]

Change log is not required in a doc-only pull request. We push every doc of every module to docs.microsoft.com in every release :)

[blueww]

@isra-fel
I have removed the change log, please help to check.

[isra-fel]

LGTM! Thanks