Remove unnecessary document file

[aleksdmladenovic]

This file is not used in our documentation but it exists in docs directory.

https://github.com/TraceMachina/nativelink/blob/main/web/platform/src/content/docs/docs/introduction/contributors.mdx

That file, introduction/contributors is not referenced in starlight.conf.ts either.

nativelink/web/platform/starlight.conf.ts

Lines 36 to 53 in e6eb5f7

	{
	label: "Getting Started",
	collapsed: true,
	items: [
	{
	label: "Introduction",
	link: `${docsRoot}/introduction/setup`,
	},
	{
	label: "NativeLink On-Prem",
	link: `${docsRoot}/introduction/on-prem`,
	},
	{
	label: "Other Build Systems",
	link: `${docsRoot}/introduction/non-bre`,
	},
	],
	},

That file's content also doesn't make sense and it even includes typo of started to starget.

nativelink/web/platform/src/content/docs/docs/introduction/contributors.mdx

Line 3 in e6eb5f7

description: "Get starget with NativeLink"

I think that file is created temporarily while development but not removed after we no longer needed that one.

[aleksdmladenovic]

Check this issue and PR plz. Thanks.

cc: @allada, @MarcusSorealheis, @blakehatch, @SchahinRohani