fix spec text to yield undersized final chunk on exhaustion

Author: michaelficarra

spec.emu

@@ -21,7 +21,10 @@ copyright: false
       1. Let _buffer_ be a new empty List.
       1. Repeat,
         1. Let _value_ be ? IteratorStepValue(_iterated_).
-        1. If _value_ is ~done~, return ~unused~.
+        1. If _value_ is ~done~, then
+          1. If _buffer_ is not empty, then
+            1. Perform Completion(Yield(CreateArrayFromList(_buffer_))).
+          1. Return ~unused~.
         1. Append _value_ to _buffer_.
         1. If the number of elements in _buffer_ is ℝ(_chunkSize_), then
           1. Let _completion_ be Completion(Yield(CreateArrayFromList(_buffer_))).