This is documentation for the first set of refactoring-related features,
all based on the new "moved" blocks in the Terraform language.
I've named the documentation section "refactoring" because in previous
discussions with users that seems to be the term they use to describe the
underlying need.
"moved" blocks are our first language feature intended to meet that need,
although it probably won't be the last as we consider other requirements
in later releases. My intent here is that once we've published this it
should eventually end up being the first result for a web search for the
topic of Terraform refactoring.