* Change `UnpackError` with `UnpackDefect`
The deprecation warning for `UnpackError` exception raised by some
`inline` procedures in the Nim standard library propagates to the user
code. If the user code has a requirement for building without warnings
this is a problem for the successful execution of the tests. In order
to resolve this, all occurrences of `UnpackError` in the Nim code base
are changed to `UnpackDefect`. Only the type alias is retained to not
break other people's user code since `UnpackError` is exported type.
* Remove the catching of `UnpackDefect`
Defect exceptions should not be cached, because they indicate problem in
the API usage. The code in `nimblesocket.nim` is rewritten to first
check whether there is a value set into the `knownDomain` variable from
the `Option` type before usage.
* Error -> Defect for defects
The distinction between Error and Defect is subjective,
context-dependent and somewhat arbitrary, so when looking at an
exception, it's hard to guess what it is - this happens often when
looking at a `raises` list _without_ opening the corresponding
definition and digging through layers of inheritance.
With the help of a little consistency in naming, it's at least possible
to start disentangling the two error types and the standard lib can set
a good example here.
* Consider proc as a pointer type in options
* Add version annotation for SomePointer having proc in options
* Log procs as pointers for options in changelog
* Add >>= operator to Options
* options.bind callback signature: A -> Option[B]
* Use `flatMap` as the name of the Option bind operation.
* Rename Options test "bind" to "flatMap"
* CR from @dom96: Remove spaces inside of check() call
