Fix typo

Author: eric-haibin-lin

tokenization.py

@@ -99,7 +99,7 @@ def convert_ids_to_tokens(inv_vocab, ids):
 
 
 def whitespace_tokenize(text):
-  """Runs basic whitespace cleaning and splitting on a peice of text."""
+  """Runs basic whitespace cleaning and splitting on a piece of text."""
   text = text.strip()
   if not text:
     return []