fixed typo in docs

docs/reference.md

@@ -400,7 +400,7 @@ This example copies the key-value table `thing`:
     ```
 
 Table comprehensions, like list comprehensions, also support multiple `for` and
-`when` clauses. In this example we use a `where` clause to prevent the value
+`when` clauses. In this example we use a `when` clause to prevent the value
 associated with the `color` key from being copied.
 
     ```moon

todo

@@ -1,5 +1,10 @@
 # TODO
 
+-- error when assining a loop whose body doesn't end in expression
+
+x = for x in y
+  y = 100
+
 -- seems like running in moon messes up require order
 
 - don't reuse _, put a local on it, so we don't keep around trash