fix: keep the same slash with system

[aliuq]

Forcing the direction of the slash to be specified can cause inconsistencies on different systems

Example, the methods backSlash always added a to right slash in the path end, in linux, this is wrong path charcter

unplugin/src/webpack/index.ts

Lines 106 to 113 in 6e419d1

	// if the resolved module is not exists,
	// we treat it as a virtual module
	if (!fs.existsSync(resolved)) {
	resolved = plugin.__virtualModulePrefix + backSlash(resolved)
	// webpack virtual module should pass in the correct path
	plugin.__vfs!.writeModule(resolved, '')
	plugin.__vfsModules!.add(resolved)
	}

unocss/unocss#797
unocss/unocss#931

[userquin]

@aliuq maybe #84 supersedes this PR?

[aliuq]

@aliuq maybe #84 supersedes this PR?

Respect for all user's consideration of slash, either way, the existing problem can be solved

[antfu]

Test failed, I guess #84 is the more desired fix. Thanks.

[aliuq]

@userquin u are right, an additional method is needed to handle the paths associated with the module