[#20604] This commit addresses a documentation issue highlighted in #206...

...04.

With out this patch, the documentation for hiera is inconsistent in how it shows strings with variables in them. On one page it shows them quoted (this is correct) and on another, it shows this unquoted (this is wrong).
This leads to confusion by users and customers and sometimes difficult to track down errors during puppet runs.

There are graphics on the hiearchies page that still needs to be updated (./images/hierarchy1.png and ./images/hierarchy2.png )