prefer-spread: Fix more .concat cases

[fisker]

1. Support fix empty .concat() call.
2. If all fixable, auto fix multiple arguments, remove .concat(...).
3. If some arguments at beginning are fixable, auto-fix code with them and keep .concat(...) with rest arguments.
4. If FIRST argument is not fixable, suggestion will fix FIRST argument and fixable arguments after first arguments, this can reduce one step when apply suggestions.
5. .concat(...a) no auto-fix, no suggestions, as we don't know what a is.
6. Trailing comma will be inserted if last array literal argument or original array literal has it.

Fixes #1041

[sindresorhus]

Shouldn't this be:

Suggested change

	1 | [1, 2,]␊
	1 | [1, , 2]␊

?

[fisker]

No,

> [1,].concat(2)
[ 1, 2 ]
> [1, , 2]
[ 1, <1 empty item>, 2 ]

It fixed in this way, because 2 inserted after 1, and the old [1,] has trailing comma, we keep it, so [1, 2,] is correct.

[sindresorhus]

Ok. I misunderstood how concat works with holes. I assumed [1,] would create 1 + a hole, but you need [1,,] to get a hole.