Fix Source Link issues caused by `#` usage in paths

[PathogenDavid]

Turns out the #'s we use for organizational folders break Source Link in many contexts, seemingly because the # is not being escaped as %23.

Ideally this should just be fixed externally, I've reported the issue to the relevant parties here:

• Visual Studio: https://developercommunity.visualstudio.com/t/-symbol-in-file-path-breaks-NET-Sour/10080583
• VSCode: https://github.com/OmniSharp/omnisharp-vscode/issues/5290
• Rider: https://youtrack.jetbrains.com/issue/RIDER-79266/-symbol-in-file-path-breaks-Source-Link

If this doesn't get fixed upstream, I think we could potentially fix this by generating our own sourcelink.json which has the # pre-escaped. IE:

{
  "documents": {
    "/_/*": "https://raw.githubusercontent.com/MochiLibraries/Biohazrd/f888ef20336e649f9cbc1fe0aeb4aae6b29d70db/*",
    "/_/external/assert.xunit/*": "https://raw.githubusercontent.com/xunit/assert.xunit/f1d3aeb9999a7c64a1bd7b3f513dbba6f76beba7/*",
    "/_/Biohazrd/#Declarations/*": "https://raw.githubusercontent.com/MochiLibraries/Biohazrd/f888ef20336e649f9cbc1fe0aeb4aae6b29d70db/Biohazrd/%23Declarations/*"
  }
}

However I'd definitely rather not deal with that.

(Thanks to @js6pak for bringing this to my attention.)