[dcl.decl] Move requires-clause into declarator.
[dcl.fct] Exlude constraints from the type of a function.
[edit] Update editorial comments.
[dcl.fct.def] Remove unnecessary section.
[class] Remove unnecessary section.
[dcl.fct] Match requires clauses for function declarators.
[dcl.decl] Add reference.
[edit] Regen documents.
Merge branch 'fn-decl'

Conflicts:
	concepts.html
	concepts.pdf