* Normalise types fully at the REPL
It was a bit odd that we only normalised the scope of function types and
not the arguments, and I can't remember the reason for that if there
even was one.
* Better way of using nf_metavars_threshold
If a term is getting big and probably needs normalising, we now have a
sizeLimit flag in quote, so we can use that instead of checking the size
afterwards. This is a handy heuristic for speeding up unification when
there's a term with lots of suspended computation. Fixes#1991
* Skip forced arguments in conversion check
This isn't always safe - we have to have also checked the type of the
things we're converting - but in the place where it is safe it can be a
pretty significant saving.
* Use Closures, not NF, in Binders for normal forms
This means we don't need to reduce argument types during unification if
we don't need to. Also, we now try to avoid reducing closures during
unification if they are unified with a metavariable. Together, this
saves a huge amount of unnecessary evaluation in programs that do a lot
of compile time evaluation.
* Didn't mean to update idris2api.ipkg
* Fix dodgy merge
