Link tool not available

The document is pretty old and references a "Link tool" I could not find.
I reckon instead it would be better to specify the Assembly Linker tool in https://docs.microsoft.com/en-us/dotnet/framework/app-domains/build-multifile-assembly .
And suggest the following syntax:

`al NumberUtil.netmodule StringUtil.netmodule /out:UtilityLib.dll /target:lib`

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#### Document Details

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* ID: bb9b4b39-813f-ed23-3cb7-682766b3cfaa
* Version Independent ID: c3216a96-76a2-21aa-2072-0328725cd3cb
* Content: [Language independence and language-independent components](https://docs.microsoft.com/en-us/dotnet/standard/language-independence#attributes)
* Content Source: [docs/standard/language-independence.md](https://github.com/dotnet/docs/blob/master/docs/standard/language-independence.md)
* Product: **dotnet**
* Technology: **dotnet-standard**
* GitHub Login: @gewarren
* Microsoft Alias: **gewarren**