lang: Allow a list of strings in the resource name

This adds a core looping construct by allowing a list of names to build
a resource. They'll all have the same parameters, but they'll
intelligently add the correct list of edges that they'd individually
create.

Constructs like these are one reason we do NOT have actual looping
functionality in the language, and it should stay that way.

docs/language-guide.md

@@ -262,6 +262,24 @@ Please note that at the moment, you must specify a full metaparams struct, since
 partial struct types are currently not supported in the language. Patches are
 welcome if you'd like to add this tricky feature!
 
+##### Resource naming
+
+Each resource must have a unique name of type `str` that is used to uniquely
+identify that resource, and can be used in the functioning of the resource at
+that resources discretion. For example, the `file` resource uses the unique name
+value to specify the path.
+
+Alternatively, the name value may be a list of strings `[]str` to build a list
+of resources, each with a name from that list. When this is done, each resource
+will use the same set of parameters. The list of internal edges specified in the
+same resource block is created intelligently to have the appropriate edge for
+each separate resource.
+
+Using this construct is a veiled form of looping (iteration). This technique is
+one of many ways you can perform iterative tasks that you might have
+traditionally used a `for` loop for instead. This is preferred, because flow
+control is error-prone and can make for less readable code.
+
 ##### Internal edges
 
 Resources may also declare edges internally. The edges may point to or from