Tweak the scope of type: ignore comment (#114)

Fixes python/typing#292

Author: ilevkivskyi

pep-0484.txt

@@ -102,8 +102,8 @@ The meaning of annotations
 
 Any function without annotations should be treated as having the most
 general type possible, or ignored, by any type checker.  Functions
-with the ``@no_type_check`` decorator or with a ``# type: ignore``
-comment should be treated as having no annotations.
+with the ``@no_type_check`` decorator should be treated as having
+no annotations.
 
 It is recommended but not required that checked functions have
 annotations for all arguments and the return type.  For a checked
@@ -1349,8 +1349,10 @@ error refers to::
       'not_found': http.client.NOT_FOUND  # type: ignore
   }
 
-A ``# type: ignore`` comment on a line by itself disables all type
-checking for the rest of the file.
+A ``# type: ignore`` comment on a line by itself is equivalent to
+adding an inline ``# type: ignore`` to each line until the end of
+the current indented block. At top indentation level this has
+effect of disabling type checking until the end of file.
 
 If type hinting proves useful in general, a syntax for typing variables
 may be provided in a future Python version.