avoid linking to substrate.io

[kianenigma]

I see that the pallet template links a lot to substrate.io, and I want to suggest you to update to linking to better rust-docs instead of those.

PaperMoon and a few other areas already in the process of deprecating the website.

I have worked with Daan already to show that a pallet template can be "backed" by links to polkadot-sdk-docs in a reasonably good way, for example https://github.com/paritytech/polkadot-sdk/pull/4684/files

related paritytech/polkadot-sdk#5118

[tsenovilla]

Hey @kianenigma 😄. I've been working in the pallet template these days and just submitted a PR:

• feat: improve pallet template generation #261

In this version there's no links to substrate.io but to the polkadot-sdk-docs :)

[AlexD10S]

Closed with #272