Binding dired-up-directory to "b" by default

[Gabriel Santos]

Greetings,

Sorry if this was previously discussed, but is there a reason for not
binding `dired-up-directory' to "b" by default?

This would make a good fit with the current configuration of `dired-mode-map',
where "f" runs `dired-find-file', which, besides finding (opening) a
file, can also go down a directory.

I thought of sending a patch, but now I think it's best to hear others'
opinions first.

Best regards,

--
Gabriel Santos