Feature: Add remark_call extrinsic to pallet-utilities about substrate

[ggwpez]

Nevertheless, a possible indexer (i.e. Subscan) would need to inspect all extrinsic nested in batches in order to get the associations between the mark and the calls. We would want a fast solution to identify such relations.

What is the problem of this? You only need to inspect the batches that emitted a remark(Mark*) event and can ignore the other ones. It wont get faster than this (maybe write it in Rust 😆).

This call should not be nested by batches to avoid an indexer going through all calls of a batch. An indexer would only need to identify those remark_call extrinsic at the top level.

I dont think it makes sense to change the runtime to optimize for such nieche off-chain use-cases. You could already look only at top-level remarks.

[lemunozm]

Make sense, probably too niche a use case. Thanks for the suggestions