bug#2137: 23.0.60; Saving Rmail buffer does not show the "Saving file ..." message

[Richard M Stallman]

    save-buffer is not enough either in order to handle `autosave' (which
    was the original reason for my using write-region-annotate-functions
    rather than write-contents-functions).

That is true -- the implementation of saving for Rmail buffers needs
to handle auto-save one way or another.  That doesn't necessarily mean
it has to work through this hook.

    >     The simplest fix is to simply always output the message rather than 
only
    >     for files larger than 50KB.
    > That would be easy, but not quite the most convenient behavior.

    What would be the harm?

Nowadays, I guess it is ok to display the message for all files.