Remove optional.defs because "engaged" and "disengaged" aren't used anymore.
Explicitly wrap the invocation_type declarations.

<wbr> doesn't work on Firefox, and these don't look good on 1 line anyway.
Fix "the the" in optional.object.assign.
Remove a Requires attribute that I missed from N4078.
Capitalize all function attributes.

One uncaptialized attribute was a member variable, so I wrapped it in <code> instead.
Remove extraneous parentheses and a "the expression" from optional.relops.
Add "experimental/" to the shared_ptr_arrays feature-test macro as specified by N4077.
Fix a <cxx-notes> that was specified as a <cxx-remarks> in N3920.

I transcribed this part of the paper wrong in commit 302ca0b93d.
Update the standalone HTML file.