docs(snix/docs/TODO): drop serde_qs bigtable TODO

This was already migrated to use a BigtableParameters struct, similar to
other backends.

Change-Id: Icc8a4902a6f24ce4a7f965abc800726b09030cb3
Reviewed-on: https://cl.snix.dev/c/snix/+/30470
Reviewed-by: Jonas Chevalier <zimbatm@zimbatm.com>
Autosubmit: Florian Klink <flokli@flokli.de>
Tested-by: besadii

snix/docs/src/TODO.md

@@ -137,8 +137,7 @@ This requires some more designing. Some goals:
       "near" store URL.
 
 ### Store Config
-   There's already serde for some store options (bigtable uses `serde_qs`).
-   We might also have common options global over all backends, like chunking
+ - We might also have common options global over all backends, like chunking
    parameters for chunking blobservices. Think where this would fit in.
  - Rework the URL syntax for object_store. We should support the default s3/gcs
    URLs at least.