Some sync/backfill format nits

[dapplion]

Proposed Changes

When working on unrelated changes I noted:

• An unnecessary closure left by a commit of some guy named @dapplion that can be removed
• match statements that can be simplified with the new let else syntax
• instead of mapping a result to ignore the Ok value, return

[michaelsproul]

Looks good, just code blocks moving around while retaining the same semantics. Happy to merge as-is or with that extra closure removed