MaxNumConcurrentStreams: Update proposed clarification text in all documents.

[willchan]

This updates the concurrent streams in the XML and updates the HTML too (which picked up some other changes).

[mnot]

"For implementors it is recommended that this value be no smaller than 100" - what is the significance of "for implementers" here?

I'm concerned this language is ambiguous enough to cause trouble. E.g., some may read it as pure advice; others might take away that values smaller than 100 can be assumed to be 100. Best way to specify is with MUST/SHOULD/MAY, identifying who it applies to (sender / recipient), and ideally specifying what should happen on both ends of the wire (when generating and receiving).

[willchan]

I agree this is ambiguous. I snuck in a short explanation there. I feel like we should take this back to the working group mailing list. I propose we either commit as is, as my extra explanatory clause is innocuous, and open an issue to resolve the ambiguity. Or I can withdraw this pull request for now, go back to the mailing list, and proceed with the flow control pull request first.

[mnot]

I'm happy to merge now and note an issue; just trying to minimise the number of such edits we cause with each change, as they have a tendency to stack up.