Ledger Substrate issues

[chidg]

Many users are confused by the limitations of Ledger on substrate, and don't understand why they can't access funds which they have sent to an address on a chain which is not supported by a Ledger app, or else corresponds to an address derived by a Ledger app for a different chain.

In order to reduce this confusion, we should do the following:

• write a blog post about how Ledger works on Substrate, what the limitations are, and what the choices are for users
• Include a UI element in the Connect Ledger account screen for Polkadot Ledger accounts linking to this blog post
• On the signing approval screen in the popup, when decoding the transaction, if the recipient address is one of the accounts in Talisman, detect if that account is a Ledger account and if the transaction is on a non-supported chain. If so, show a warning.
• If pasting an address in the send funds UI, detect if the address corresponds to an existing Ledger account on another chain and show a warning