"BOLT 4: Remove legacy format, make var_onion_optin compulsory."
This also renamed the redundant "tlv_payload" to "payload", so we
replace "tlv_tlv_payload" with "tlv_payload" everyhere!
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
```
make check-source-bolt CHECK_BOLT_PREFIX="--prefix=BOLT-route-blinding" BOLTVERSION=guilt/offers
```
Other than textual changes, this does:
1. Ensures we put total_amount_msat in onion final hop (reported by @t-bast).
2. Require that they put total_amount_msat in onion final hop.
3. Return `invalid_onion_blinding` exactly as defined by the spec (i.e. less
aggressive when we're the final hop) (also reported by @t-bast, but I already
knew).
See: #5823
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-EXPERIMENTAL: `offers` breaking blinded payments change (total_amount_sat required, Eclair compat)
You can use rs->nextcase, but we don't always keep that around, so
keep a flag in onion_payload.
We'll use this in the "do we need to return a blinded error code"
patch.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
