[website] Document how to set usertags in BTS

Hi Paul,

I was just about translating https://www.debian.org/Bugs/Reporting, and I would
like to propose a small changing here.

	<quote>You can set usertags for multiple users at bug submission time by 
	       including multiple User pseudo-headers, each Usertags pseudo-header
	       sets the usertags for the last User pseudo-header.
	</quote>

I read this as "if more than one 'User' pseudo-headers are used, only the
last one is used, all others are ignored" ('the last one wins' concept).


The term "last" should probably be changed into something like "in the line before"
or "the last set before" ?

At least I missunderstood it, the way as it is now.


A patch is attached, leading to this sentence:


<p>You can set usertags for multiple users at bug submission time by
including multiple User pseudo-headers; each Usertags pseudo-header
sets the usertags for the last user set before via User pseudo-header. This is especially
useful for setting usertags for a team with multiple users, setting
usertags for multiple teams, or setting the
<a href="https://wiki.debian.org/Teams/Debbugs/ArchitectureTags">architecture usertags</a>
for bugs affecting multiple architectures.
</p>


Holger