docs(snix/docs/TODO): drop Error cleanup TODO

Migrated to #134.

Change-Id: I555219085fea8c192e769cb7b5357321087ffdf7
Reviewed-on: https://cl.snix.dev/c/snix/+/30479
Autosubmit: Florian Klink <flokli@flokli.de>
Reviewed-by: Jonas Chevalier <zimbatm@zimbatm.com>
Tested-by: besadii

snix/docs/src/TODO.md

@@ -35,21 +35,6 @@ the resulting diff noise on resulting mismtaches).
 in resulting store paths.
 
 
-## Error cleanup
- - Currently, all services use snix_castore::Error, which only has two kinds
-   (invalid request, storage error), containing an (owned) string.
-   This is quite primitive. We should have individual error types for BS, DS, PS.
-   Maybe these should have some generics to still be able to carry errors from
-   the underlying backend, similar to `IngestionError`.
-   There was an attempt to give PS separate error types (cl/11695), but this
-   ended up very verbose.
-   Every error had to be boxed, and a possible additional message be added. Some
-   errors that didn't wrap another underlying errors were hard to construct, too
-   (requiring the addition of errors). All of this without even having added
-   proper backtrace support, which would be quite helpful in store hierarchies.
-   `anyhow`'s `.context()` gives us most of this out of the box. Maybe we can
-   use that, using enums rather than `&'static str` as context in some cases?
-
 ## Documentation
 Extend the other pages in here. Some ideas on what should be tackled:
  - Document what Tvix is, and what it is not yet. What it is now, what it is not