[nginx] Document modules as a way to patch nginx?

[Guillaume Outters]

Last night, while trying to progress on my {{.}} syntax in config files 
by recompiling and recompiling my nginx, I looked at 
nginx_upstream_check_module source and incidentally discovered that 
nginx modules where both powerful and easy to create.

So easy and powerful that the [PATCH] I submitted in september and 
october could be quickly set into a module, integrating nicely in nginx 
build.

So I wondered: couldn't this way of playing with nginx internals be 
advertized as a notice in 
http://nginx.org/en/docs/contributing_changes.html?
Something like:

----------------
Many changes to nginx core source, including those requiring to patch 
nginx, can be implemented as modules, which are easy to create, easy to 
publish, and easy to integrate to nginx.
Before trying to contribute to nginx source, please contemplate 
packaging your changes as a module. Thus:
- you will be able to test it in a clean way with your installation, 
before submitting it to the core
- your specific needs can be implemented there without conflicting with 
the community's ones
- you will be able to distribute it long before it is integrated to 
nginx
- you will be able to run it on the very release of nginx your 
production uses
----------------

-- 
Guillaume