tiny_markdown example fails otherwise.
It were broken with mine
cf8f511 "add more tests to position handling and fix them"

- rename `get_byte`->`match_dot`, add `match_char_range`
- abuse choice variants reset position by themself
- abuse optional rule reset position by itself
- simplify sequence with resetting position after block instead of after each element
- unify `+` and numbered repetition
- strip actions body

Also fix issue with nested repetition collection:
- names `_ary` and `_count` were erroneously reused