Changes in emails sent by the forge

Hi all,
I've pushed a couple of updates to the batrachomyomachia bot. As a 
consequence:
- patch versions sent by the bot will no longer be threaded
   (this was an explicit ask)
- single commits will no longer carry an additional cover letter
- pure rebases will no longer generate a new patch version
- the cover letter / additional text added by the bot after the patch 
divider is now easier to read and provides instructions on how to fetch 
the pull request using git commands

My recommendation is that everyone run
git remote add forge-upstream [email protected]:gcc/gcc
if you have a forge account or
git remote add forge-upstream https://forge.sourceware.org/gcc/gcc.git
if you don't on your local clones.

This will make it possible to simply copy paste the instructions that 
will come with each patch sent by the bot.

I have updated the guidance on https://gcc.gnu.org/wiki/UsingForge
to make use of this remote name.

Please reach out over email or IRC should you face problems with the forge.

Cheers,
Claudio