[m-users.] Two new tools for developers using Emacs

[fabrice nicol]

Hi everyone,

This message is to announce two tools intended for programmers who 
prefer Emacs over Vim as a choice platform:

+ A fork of Matthew Carter's *metal-mercury-mode*, with seven added 
*M-x* commands to reach most Mercury declarations in specific window 
buffers:

https://github.com/fabnicol/metal-mercury-mode/wiki

+ A fork of emacs 28.0 vanilla source code to add support for Mercury in 
lib-src/etags.c:

https://github.com/fabnicol/mercury-emacs/wiki


This means that Emacs has to be rebuilt from source code, as *etags* is 
not a package but an inlined capability.

To facilitate testing, I've included a binary package for Ubuntu 20.10 
in the github release section:

https://github.com/fabnicol/mercury-emacs/releases/tag/1.0


Overall, these patches work fine in my ongoing development practice, 
with admitted limitations.

User feedback will be appreciated.

Best,

Fabrice Nicol