test for files rendered matching start/end content

This is currently expected to fail with the following type of messages:

       expected Chef run to render "/tmp/template" matching:

       end with "content!"

       but got:

       This is content!

Unsure if this is a bug here, with rspec matchers, or with Chef file renderer for file/templates, but I exposed it while trying to write a test with ChefSpec, and was able to reproduce it in ChefSpec's cucumber testing.

I was also testing heredocs when I found this, wasn't sure if I should add/modify a resource in the emaples directory or not. Something akin to:
```ruby
file '/tmp/file-heredoc' do
  content <<-EOF
This is content!
EOF
end
```
With no changes to the tests, this will not fail. However, attempting to test for the end_with as a positive case, i.e. "it should end with content!" will fail.