OrchestrateLang v0.11.0

The language owns its own errors.

Fixed

• String concatenation no longer consumes its operands. a + b moved both sides, so a
  string could be used exactly once and s + s did not compile at all
  (error[E0382]: use of moved value). Addition now borrows: let c = a + b leaves both
  a and b usable, and a + a works. int and float addition is unchanged in
  behaviour and in cost.
• A match on a unit enum variant that binds a value is a type error, naming the variant
  and how to write it, instead of rustc's "expected tuple struct or tuple variant, found
  unit variant". The mirror case is caught too: a variant that carries a value and is
  matched without binding it. So is a variant that does not exist, which now lists the ones
  that do.
• A try block whose body waits compiles. try { fetch(1) } catch e { 0 }, where
  fetch is a task, reached rustc as "await is only allowed inside async functions"
  because the block generated a synchronous closure. A block that waits now generates an
  async block instead, so ? still works and the handler may wait too. A block that does
  not wait generates exactly what it did before.
• A fn, task, or process that names top-level state says so. Top-level lets
  belong to the instance and only hooks reach them — a spawned task can run while a tick
  holds that state, so the restriction is deliberate. It used to surface as rustc's
  "cannot find value in this scope"; it is now a diagnostic naming the function, the
  binding, and the way out.

Changed

• docs/roadmap.md no longer describes sandboxed serverlets as unshipped (0.9.0) or C# as
  upcoming (0.10.0).