Comment on withBinaryFile seems wrong

It says

The action /should/ close the file when finished with it so the file does not remain open until the garbage collector collects the handle

but like withFile and withFileBlocking, withBinaryFile uses withFile', which passes True as the argument close_finally to withOpenFile', so it seems like the handle is indeed closed in the end. It seems like the comment should thus say the same as for withFile and withFileBlocking:

The handle will be closed on exit

Originally introduced in f90487ca.