Add better docs about duplicate resource failures
Add better docs about duplicate resource failures

This commit adds better inline documentation
explaining how replicate resource definitions can
occur if the resource exists and does not have
matching parameters.
DavidS/puppetlabs-stdlib,puppetlabs/puppetlabs-stdlib,fuel-infra/puppetlabs-stdlib,HelenCampbell/puppetlabs-stdlib,yadavnikhil/puppetlabs-stdlib,jbondpdx/puppetlabs-stdlib