Use bsc.exe to figure out rescript version

[nojaf]

Fixes #1079

I'm also in a little weird position where I use nvm on Mac, and somehow node is not always on my path anymore. This worked in the past, but is somehow broken for me, so I took a look in how I can get the LSP server working without depending on Node being present.

Turns out, the only thing I bump into is the initial rescript version call.
That will run node_modules/.bin/rescript which in the latest alpha has

#!/usr/bin/env node
...

For all the other stuff where we shell out to bsc, rescript-editor-analysis, we target the platform specific executable.

So, in this PR, I'm changing the version check to do the same. bsc.exe -v also produces the version we are after, prepended with ReScript.

[zth]

I have a hunch there might be a reason we used the rescript bin instead, but can't fully remember. Could you check what older ReScript versions gives you when you call that command? ReScript 9 & 10.

[nojaf]

ReScript 11.1.4
ReScript 10.1.4
ReScript 9.1.4

all works out

[zth]

Great, thanks for checking! Then just a changelog and we're good to go.