FR: `include_surrounding_whitespace` should adjust whitespace characters included based on mode

[chrisgrieser]

Is your feature request related to a problem? Please describe.
Enabling include_surrounding_whitespace often leads to technically correct, but somewhat unexpected behavior.

Given this text:

local obj = {
	text = "foobar", -- comment
	number = 123,
}

For instance, deleting the --comment via @comment.outer results in:

local obj = {
	text = "foobar", number = 123,
}

Which is technically correct – surrounding whitespace was included – but very unintuitive behavior.

Describe the solution you'd like
include_surrounding_whitespace should not include line breaks if the text object is characterwise.

Describe alternatives you've considered
Simply disabling include_surrounding_whitespace entirely (which is a waste, since it's in principle a nice feature)

Additional context
There are a few other issues like #575 which seem to be related to this problem.