Don't use @roblox prefix for non-roblox definition + documentation files

[WolfGangS]

As mentioned in issue #970 Secondlife is looking to add luau

In my efforts to create typedefs etc, i have found that the api documentation format requires the use of @roblox prefix for every entry to be picked up.

I suspect this may be the spot at fault

luau-lsp/src/LuauExt.cpp

Lines 56 to 60 in a005567

	Luau::LoadDefinitionFileResult registerDefinitions(Luau::Frontend& frontend, Luau::GlobalTypes& globals, const std::string& definitions)
	{
	// TODO: packageName shouldn't just be "@roblox"
	return frontend.loadDefinitionFile(globals, globals.globalScope, definitions, "@roblox", /* captureComments = */ false);
	}

it would be nice to clean this up, I'm still reading over the project, to see if i could contribute this change myself and how it would be controlled / what it would affect.

I suspect tying it into the luau-lsp.platform.type config may not work out as I thought it would at first.

An alternative may be issue #271 but i see that is still blocked on #885

[JohnnyMorganz]

Indeed I would like to fix this with #885, but I haven't got round to fixing the test failure yet. Some users rely on the ordering of the definitions file loading which we lose when we switch to a dictionary. I was thinking of maybe just hard coding it so that Roblox shows first if it exists.

The reason it's hardcoded to Roblox right now is mainly because Roblox api docs were the main ones currently in use, which use that name

[ffrostfall]

Bump. Writing type definitions for Lute and ran into this

[deviaze]

Bump [2]. Wanted to write docs for seal's globals and ran into this too.

[itsmath]

Bump³. Wanted to write docs and ran into this just like these two.