Add pattern matching/fusion article

[haxscramper]

No description provided.

[haxscramper]

This article is ready to be published, I'm just doing occasional fixups when something comes up.

[haxscramper]

Because changes in fusion were not conveyed in 1.4.4 post at all I added this to the article too (along with main pattern matching description)

[narimiran]

Because changes in fusion were not conveyed in 1.4.4 post at all

1.4.4 comes with the old version of fusion.

[haxscramper]

Fusion was ubundled from nim, and now is just a library, no? nim-lang/Nim#16925

[narimiran]

Why closing it? I planned to publish it next week.

[haxscramper]

If I knew this I wouldn't close it. But I didn't and decided that I would be waiting god-knows-how-long before someone finally comes to conclusion about what fusion is, how it is shipped, what version, and so on. So I decided it would be easier to publish it myself sometimes later.

[haxscramper]

I will reopen now