style(rust): format decoder policy bridge

Apply the repository formatter to the sequence-decoder policy bridge introduced in the preceding decompression refactor. The change is formatting-only.

Test Plan: cargo +nightly fmt --manifest-path rust/Cargo.toml --all -- --check

rust/src/zstd_decompress_block.rs

@@ -78,9 +78,7 @@ pub struct ZSTD_rustSequenceDecoderPolicy {
 
 const _: () = {
     assert!(offset_of!(ZSTD_rustSequenceDecoderPolicy, force_short) == 0);
-    assert!(
-        offset_of!(ZSTD_rustSequenceDecoderPolicy, force_long) == size_of::<c_int>()
-    );
+    assert!(offset_of!(ZSTD_rustSequenceDecoderPolicy, force_long) == size_of::<c_int>());
     assert!(size_of::<ZSTD_rustSequenceDecoderPolicy>() == 2 * size_of::<c_int>());
 };