[2.7] bpo-33885: Replace "hook function" with "callable" (GH-7765). (#7885)

(cherry picked from commit c45cb479074b5d25f0d382d3109f527520a9f03c)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

Doc/library/urllib.rst

@@ -166,9 +166,9 @@ High-level interface
 
    The second argument, if present, specifies the file location to copy to (if
    absent, the location will be a tempfile with a generated name). The third
-   argument, if present, is a hook function that will be called once on
+   argument, if present, is a callable that will be called once on
    establishment of the network connection and once after each block read
-   thereafter.  The hook will be passed three arguments; a count of blocks
+   thereafter.  The callable will be passed three arguments; a count of blocks
    transferred so far, a block size in bytes, and the total size of the file.  The
    third argument may be ``-1`` on older FTP servers which do not return a file
    size in response to a retrieval request.