This rewrite of the "Configuration Syntax" page now gives some more detail
on the top-level structural constructs and de-emphasizes the name "HCL"
as subordinate to "the Terraform language".
It also now includes some commentary on valid identifiers and comments,
and issues around character encodings and line endings.
In addition, we now have a new "Expressions" page that replaces the old
"Interpolation Syntax" page, covering the expression language features
we inherit from HCL and how they behave in the context of Terraform.
The "Expressions" page currently links to a page about the built-in
functions which does not yet exist. This will be created in a later
commit.