non-`file:` URIs in library/userThirdParty settings don't work

my extension generates a LuaLS userThirdParty bundle dynamically from Factorio's doc files (from the local game install, generally). I'm working on trying to switch to using a virtual FS provider for these files instead of cluttering up real workspace-associated folders with them. I've registered as the provider for fmtk: uris, and i can open all the files for the generated bundle in vscode in editor tabs, but LuaLS won't load them as libraries.

I set

"Lua.workspace.userThirdParty": [
        "fmtk:/luals"
    ],

in my settings.json, instead of setting the generated folder path as i had done previously, but LuaLS seems to have completely ignored it.

I also tried

    "Lua.workspace.library": [
        "fmtk:/luals/factorio/library"
    ],

but that also seems to ignore anything that isn't a plain file path.

まず、報告に示されている fmtk: 仮想ファイルシステムプロバイダーと Lua.workspace.userThirdParty および Lua.workspace.library の設定を使って問題を再現します。これらの設定がライブラリパスをどのように解決するかを追跡します。ファイル URI ではない URI が無視されずライブラリとして読み込まれ、その動作を対象とするリグレッションテストがあれば完了です。