parser, fmt: fix match with multi-commmented branchs (fix #19880)

[yuyi98]

This PR fix match with multi-commmented branchs (fix #19880).

• Fix match with multi-commmented branchs.
• Add test.

vlib\v\fmt\tests\match_with_multi_commented_branches_keep.vv

import strings

fn escape_string(s string) string {
	mut res := strings.new_builder(s.len * 2)
	for ch in s {
		match ch {
			0 // NUL (null)
			{
				res.write_u8(92) // \
				res.write_u8(48) // 0
			}
			10 { // LF (line feed)
				res.write_u8(92) // \
				res.write_u8(110) // n
			}
			13 { // CR (carriage return)
				res.write_u8(92) // \
				res.write_u8(114) // r
			}
			26 { // SUB (substitute)
				res.write_u8(92) // \
				res.write_u8(90) // Z
			}
			34,  // "
			39,  // '
			92 // \
			{
				res.write_u8(92) // \
				res.write_u8(ch)
			}
			else {
				res.write_u8(ch)
			}
		}
	}
	return res.bytestr()
}

fn main() {
}

[spytheman]

Should vfmt support such comments @medvednikov ?

[JalonSolov]

At first glance, they appear to be simple end-of-line comments, which should be supported.

However, this piece

			34,  // "
			39,  // '
			92 // \
			{

should be reformatted to

			34, 39, 92 { // ", ', \

or similar.

[medvednikov]

I think this PR is fine.

[medvednikov]

34,  // "
39,  // '
92 // \

I think this is correct, and each branch should have its own comment, without merging them.

[JalonSolov]

The problem now is that v fmt has 2 different outputs, depending on whether or not comments are there.

If the original looks like

			34,  // "
			39,  // '
			92 // \
			{

and you run it through v fmt, it will still look the same after. However, if you have

			34,
			39,
			92
			{

and run it through v fmt, it will be reformatted to

                        34, 39, 92 {

Seems pretty inconsistent formatting, to me.

[medvednikov]

I understand, I think it's fine.

It's the same with arrays for example

[1,2,3,
4,5,6]

will be vfmted to [1,2,3,4,5,6]

but if there are comments for each line, it'll be multiline