Update rustfmt to use local repo version instead of mu_devops version. (#466)

Some downstream repos updated to 2024 rustfmt.

Update the synced version of rustfmt to remove specifying a format. This
way, the edition will use the repo's Cargo.toml.

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Co-authored-by: Michael Kubacki <michael.kubacki@microsoft.com>

Author: apop5

.sync/rust_config/rustfmt.toml

@@ -5,7 +5,6 @@
 
 # Keep these options sorted in ascending order to ease lookup with rustfmt documentation.
 
-edition = "2021"                 # This would normally be picked up from Cargo.toml if not specified here
 enum_discrim_align_threshold = 8 # Vertically align enum discriminants
 force_explicit_abi = true        # Always print the ABI for extern items (e.g. extern {... will become extern "C" {...)
 hard_tabs = false                # Always uses spaces for indentation and alignment