website: document templates

While we're here, fix a broken link.

website/source/docs/configuration/interpolation.html.md

@@ -114,3 +114,33 @@ The supported built-in functions are:
       back into a list. This is useful for pushing lists through module
       outputs since they currently only support string values.
       Example: `split(",", module.amod.server_ids)`
+
+## Templates
+
+Long strings can be managed using templates. Templates are [resources](/docs/configuration/resources.html) defined by a filename and some variables to use during interpolation. They have a computed `rendered` attribute containing the result.
+
+A template resource looks like:
+
+```
+resource "template_file" "example" {
+    filename = "template.txt"
+    vars {
+        hello = "goodnight"
+        world = "moon"
+    }
+}
+
+output "rendered" {
+    value = "${template_file.example.rendered}"
+}
+```
+
+Assuming `template.txt` looks like this:
+
+```
+${hello} ${world}!
+```
+
+Then the rendered value would be `goodnight moon!`.
+
+You may use any of the built-in functions in your template.

website/source/docs/configuration/providers.html.md

@@ -9,7 +9,7 @@ description: |-
 # Provider Configuration
 
 Providers are responsible in Terraform for managing the lifecycle
-of a [resource](/docs/configuration/resource.html): create,
+of a [resource](/docs/configuration/resources.html): create,
 read, update, delete.
 
 Every resource in Terraform is mapped to a provider based