Update tools documentation.md

[LazaroOnline]

Instead of having the same docs duplicated, just reference the original from the respective GitHub docs that are always up to date.
Solves issue #353

[frankkilcommins]

Thanks @LazaroOnline but this is not needed as it relates to an older branch. No public documentation should be reference this branch explicitly.

[LazaroOnline]

So maybe the target branch should be another one.
I don't have any way to know where your official web page at https://swagger.io/docs is pulling the data from.
But these changes are still required and can be merged with the correct branch.