Revert "Merge pull request #112 from stelford/master"

This reverts commit 0289b4f2d0b7ecf4b39dc5446fd85dba28610315, reversing
changes made to 661033874cb6e89a9c2999f7c2d1d61d600b2313.

Due to a number of issues that came up in testing/exercising #18577
related to conflicts between namespaces and defining hash values, it
needs to be reverted before Hiera 1.3.0 can be released.
Merge branch 'issue/master/18577-revert-PR112-extending-yaml-syntax-support'

* issue/master/18577-revert-PR112-extending-yaml-syntax-support:
  Revert "Merge pull request #112 from stelford/master"