bug#53492: 29.0.50; Remove use of define-keymap in gnus-registry.el?

[Eric Abrahamsen]

Commit 453db25 changes the Gnus registry's key bindings to use
`define-keymap'. The problem is that the old code *added* the registry
bindings to the "M" prefix in `gnus-summary-mode-map', while the new
code *overrides* everything that was defined on that "M" prefix, in
favor of the registry's keys. There used to be a lot of commands there.

The simple solution would be to not use `define-keymap' in the registry
code, and instead use `define-key' inside the loop at
gnus-registry.el:959, defining each command individually on a "M <key>"
binding.

Another possibility would be to explicitly name the sub-keymap that's
currently hung on the "M" prefix, at gnus-sum.el:2038. Then that could
be used as a :parent in the `define-keymap' call in gnus-registry.el.

Or is there a way to attach a `define-keymap' to an anonymous prefixed
keymap?

Eric