getregionpos() returns a list of buffer segments for a given range

[justinmk]

Problem

A buffer region in Vim, is described by four parameters: {pos1}, {pos2}, {regtype}, {inclusive}

Any function that accepts only {pos1}, {pos2} must either be reworked to also accept {regtype}, {inclusive}, or the caller must manually figure out the buffer segments that map to the "region", and feed them into the function.

Feature request

Extracted from discussion in #13998 (comment)

(Main use case here: highlight-on-yank as in https://github.com/machakann/vim-highlightedyank.)

Introduce getregionpos({pos1}, {pos2}, {regtype}, {inclusive}) which returns a list of start/end positions in the buffer.