Since we no longer parse for them, we can rip them out entirely. This
gives us approximately 15% perf improvement on compilation.

The most invasive part of this change is taking the $what off of $tomes,
which affects a lot of code, but mostly in very trivial ways.

Note that we retain a nesting sample type on +loot, because that's
jetted. This way we don't have to coordinate a jet update. We eat a
+run:by to make this work, but those maps shouldn't ever be huge in
practice.

Bumps the hoon kelvin version to 136 and restores the original 137 types
inside of a `+h137` core. There we also include `+next-*` arms for
converting 137 types to their 136 equivalents.

We sprinkle `~+` on a handful of the upgrade arms to make running them
on real-world values feasible.

To accommodate the hoon 136 changes, we need to migrate all the types we
stored in state. We add an `+a236` core that contains the old types
(using hoon's `+h137`) and helpers for migrating. This includes one for
`$cage`: it's not used inside arvo proper, but will be helpful to vanes.

Upgrade from hoon 137 to 136.

Upgrade from hoon 137 to 136.

Because of how the `+load` is written, we end up touching a bunch of the
old types and their migration functions. Restructuring this to prevent
this in the future is out of scope (for now).

Upgrade from hoon 137 to 136.

Because of how the `+load` is written, we end up touching a bunch of the
old types and their migration functions. Restructuring this to prevent
this in the future is out of scope (for now).

Hoon 136 no longer includes the doccord types. This affects the xray and
pprint libraries, and removes the dprint library's raison d'être.

Removes doccords-related types and logic, and migrates the types of
bound variables.

Migrate the vases in `.starting` to the new type.

These should've been included in a33c47e but slipped through somehow.

Prior to removing doccords, presumably due to doccords parser behavior,
we allowed comments at the direct end of file, without a trailing
newline. 60af617 broke this behavior.

It's probably sane to allow comments without a trailing newline in
general, so here we update the comment parser +vul to either parse a
newline or, failing that, check for end of the string.

That library was removed in a33c47e.

And remove the old cases from the $heir. Right now they don't travel
across version boundaries anyway, so we can just drop them and their
conversion functions.

Also adds a =, to the top of +a235 so we won't need to touch it again
in the future.

We had left in a ~ preceding the tomes to remain compatible with the old
jets. But since we're moving to a new jet dashboard for the new hoon
version anyway, and we do hit this code a bunch, better to remove the
unnecessary cell.

If you =, the old hoon before the current arvo, then the context of the
current arvo shadows the old types that we want to use. Slightly
annoying, but hopefully still beats manually pointing into the old hoon
core.