RE: Document that symbol prefix "my-" (or other) should be left for users

[Drew Adams]

> > So can you give a reason why Emacs-Lisp coding conventions
> > should reserve such a prefix (or any other) for users?
> > Haven't heard any reason, so far.
> 
> I have seen people run into conflicts several times (over a
> long time frame)...  So: if you want to know if it has ever
> happened: absolutely.

The question I raised is not whether users have run into name
conflicts but why Emacs coding conventions should reserve any
given name prefix (or prefixes?) for users.

Users can run into name conflicts also if they use the same
"reserved" prefix `my-' (or `my/' or `my31459265358979535/'
or whatever).