Since %tas is the common case, this will result in smaller/shorter
representations for most piths.
Additionally, we switch from ,/pith to #/pith syntax, to more clearly
mark it as temporary.
Prefixing a path with a com will cause the path to be interpreted as a `$pith`,
aka a typed path. Instead of interpreting every element as a string, we use
hoon's atom syntaxes to read the values, and tag them with appropriate auras.
For example, `,/hi/5/0x6` becomes `[[%tas %hi] [%ud 5] [%ux 0x6] ~]`.
Dynamic elements via `()` and `[]` is also supported, and may optionally be
tagged with `aura+(etc)` syntax. For example, `,/next/ud+[+(1)]`.
Could _maybe_ be refactored to use `+nuck`, but we'd need to wrestle the output,
and we're a little stricter here anyway.
This shadows existing `,/some-wing` syntax, which... presumably does something,
but is not in active use anywhere. We might consider removing that syntax.
Eventually, we probably want this to be the primary urbit-native path type.
Invalidating existing path syntax is very invasive though, so for now we
piggy-back on "com changes the parsing mode" for a less disruptive addition.
Previously, if the pointer for a syntax error pointed to the end of the file
(and the file ended in a newline) the code snippet rendering would try to
display a line _beyond_ the end of the file, causing a crash.
Here, we detect that case, and display `<<end of file>>` instead.
This accounts for a possible race condition where ames expects a
response, but regresses into the larval state. Upon receiving the
$sign on +take, we would remain stuck as a larva. Now we check
that we have enough information to re-evolve and then start a
/larval timer to begin draining the queue.
