D4129: includematcher: separate "parents" from "dirs"

[Yuya Nishihara]

> -def _rootsanddirs(kindpats):
> +def _rootsdirsandparents(kindpats):
>      '''Returns roots and exact directories from patterns.
>  
>      roots are directories to match recursively, whereas exact directories should
>      be matched non-recursively. The returned (roots, dirs) tuple will also
>      include directories that need to be implicitly considered as either, such as
>      parent directories.

Can you update the doc to reflect this change?