Correct doctest snippet.

src/ZEO/tests/protocols.test

@@ -170,8 +170,8 @@ Note that we'll have to pull some hijinks:
     >>> with conn.root()['blob1'].open() as f:
     ...    f.read()
     b'blob data 1'
-    >>> with conn.root()['blob2'].open() as
-    ...    f: f.read()
+    >>> with conn.root()['blob2'].open() as f:
+    ...    f.read()
     b'blob data 2'
 
 Make some old protocol calls: