fix SourceLink

[ge0rdi]

This fixes regression introduced in f1516d6 .

Current sourcelink stream looks like this:

{
  "documents": {
    "\\*": "https://raw.githubusercontent.com/winsiderss/systeminformer/609ffb2547bd54741d49a4ed50efe7e6fe2922ed*",
    "D:\\a\\1\\s\\*": "https://raw.githubusercontent.com/winsiderss/systeminformer/609ffb2547bd54741d49a4ed50efe7e6fe2922ed*"
  }
}

Note that / is missing before * wildcard in URL part. That's obvious mistake.

Then there seems to be problem with source path matching.
In PDBs they look like SystemInformer\main.c, phlib\native.c (due to deterministic builds).
So they don't match \\* pattern.
With * as path pattern everything works nicely.