editors/emacs: Update to 29.3

[ashish]

Summary

I have only been able to test nox flavour only.

Mk/Uses/emacs.mk, and dependent port bumps changes are not forgotten, and are pending.

Since this is a security release, I wonder if anyone has any idea about vuxml entry ?

Thanks!

[ashish]

Add the missed CANNA distinfo.

[jrm]

Also, chase editors/emacs update.

(Added vuxml entry in e9c72a3c944e307ce9cee246ef49e05c2340bf1a)

TODO:

• Check whether editors/emacs-devel needs to be included in the vuxml entry and updated
• Verify the list of ports that need a PORTREVION bump
• More testport