docs: fix codespell flag on ADR-00021 (consequentially -> significantly)

Pre-commit's codespell hook flagged "consequentially" as a misspelling
of "consequently"; reworded to "most significantly" instead, which
reads more naturally in context.

Signed-off-by: Ryan Carbotte <ryancarbotte@gmail.com>

Author: theRTC204

docs/developing/decisions/00021-split-debuginfo-x86-64-linux.md

@@ -13,7 +13,7 @@ deciders: Ryan Carbotte
 had none, so x86_64 Linux builds silently fell back to the generic `[build]` rustflags — a per-target table
 fully replaces `[build]` rather than merging with it, so falling back meant losing every non-warning flag the
 other targets carried: the `tokio_unstable`/`uuid_unstable` cfgs, the `force-unwind-tables`/`force-frame-pointers`
-codegen flags, and, most consequentially, `split-debuginfo`. With no `split-debuginfo` set, x86_64 Linux used
+codegen flags, and, most significantly, `split-debuginfo`. With no `split-debuginfo` set, x86_64 Linux used
 rustc's platform default of `off` — full DWARF **embedded directly in the binary**, not absent. The
 `[profile.release-lto]` profile set `debug = 2` for every platform, so that embedded DWARF landed directly in
 the `.so` instead of being split into a companion file, producing a release binary noticeably larger than