[keyboard] More advanced range / list target support

[pokey]

Once we have #1002, we should improve range support as follows:

• Add support for having modifier only apply to endpoint, rather than both sides of range, like "just" would do
• Add support for having modifier only apply to last target of a list target, like "just" does
• Add support for extending the last target of a list target when creating a range; the naive approach would try to extend all targets and fail. Equivalent to "air and bat past cap"

[pokey]

See also https://github.com/cursorless-dev/cursorless/pull/2051/files#r1413953222