Update website/docs/language/values/variables.html.md

Co-authored-by: Laura Pacilio <83350965+laurapacilio@users.noreply.github.com>

website/docs/language/values/variables.html.md

@@ -329,8 +329,8 @@ Setting `nullable` to `false` ensures that the variable value will never be
 `null` within the module. If `nullable` is `false` and the variable has a
 `default` value, then Terraform uses the default when a module input argument is `null`.
 
-`nullable` only controls where the direct value of the variable may be `null`.
-For variables of collection or structural types, such as list or object types,
+The `nullable` argument only controls where the direct value of the variable may be `null`.
+For variables of collection or structural types, such as lists or objects,
 the caller may still use `null` in nested elements or attributes, as long as
 the collection or structure itself is not null.