Unexpected default from `erc-switch-to-buffer' and friends

[J.P.]

This is somewhat related to:

  https://debbugs.gnu.org/cgi/bugreport.cgi?bug=53617

Even though the existing behavior of `erc-switch-to-buffer-*' is likely
too ingrained to mess with, it may be worth noting somewhere (here, for
posterity) that the default prompt value supplied by
`erc--switch-to-buffer' to `read-buffer' for its optional DEF param is
drawn from *all* buffers for all ERC sessions:

  (read-buffer "Switch to ERC buffer: "
               (when (boundp 'erc-modified-channels-alist)
                 (buffer-name (caar (last erc-modified-channels-alist))))
  ...)


But the doc strings for `erc-switch-to-buffer' and
`erc-switch-to-buffer-other-window' seem to imply that such behavior
should only be manifest when a prefix argument was given. I wonder how
disruptive it'd be to change things up now? Probably overly so.