puppet-strings insists on redundant return value for puppet functions

Describe the Bug

When generating the documentation of a Puppet function, puppet-strings wants to see a @return tag in the comments, while the code already include the returned type.

Expected Behavior

puppet-strings should not want a @return tag.

Steps to Reproduce

Generate the documentation of a function (example taken from stdlib):

# @summary function to cast ensure parameter to resource specific value
function stdlib::ensure(
  Variant[Boolean, Enum['present', 'absent']] $ensure,
  Enum['directory', 'link', 'mounted', 'service', 'file', 'package'] $resource,
) >> String {
  # [...]
}

Note the >> String that tells what the function returns.

Environment

• Version : 2.9.0
• Platform : Any

Additional Context

Suggested by @ekohl in https://github.com/puppetlabs/puppetlabs-stdlib/pull/1239#discussion_r861254739

Start by reproducing documentation generation for the stdlib::ensure example and trace the validation that requires a @return tag. Confirm how Puppet's declared return type is parsed, then add coverage showing that a typed function needs no redundant tag; done when generation succeeds without @return and existing tests remain passing.