Fix: #105. No trailers.

[ioggstream]

This PR

• no trailers, but no normative language
• add explanation in FAQ, noting that it could be addressed in future specifications

[mnot]

If you're going to preclude trailers, you should more prominently call it a 'header field' rather than just a 'field' (including in the title?)

[ioggstream]

I thought about it. Since I was guessing whether a future extension I-D could address this point, I didn't want to be strict: but please let me know. @mnot

[mnot]

A future RFC could expand the scope of these to trailers, yes. In this draft, it's important to communicate consistently and clearly, so you should use 'header field' not just 'field'.

[ioggstream]

@mnot will do, but I won't probably make it for the next meeting.