docs(plugin-webhooks): re-anchor the dead tracker citation to the commit that decided it

One docblock site under packages/plugins/plugin-webhooks/src cited a tracker
number that answers 404: translations/index.ts:26, which says where the
per-locale provenance companion comes from. It now cites the commit in this
repository that decided it (ruling C's commit rung; no ADR records it):

- #11671 -> 09b4f4e, the extract command's --source-hashes option that
  writes the per-locale source-hashes companion beside the generated bundles,
  per maintainer ruling #12069 Option A (1 line).

The rewritten line is byte-identical to the one the six sibling translation
sets already carry. The file keeps its line count; no code token moves; no
citation number is added.

Claude-Session: https://claude.ai/code/session_01XY5uCwTjZj7884yYtyur4H
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

packages/plugins/plugin-webhooks/src/translations/index.ts

@@ -23,7 +23,7 @@ import { esESGeneratedSourceHashes } from './es-ES.source-hashes.generated.js';
  * ## The provenance companions are READ here, not merely recorded
  *
  * `os i18n extract --source-hashes` writes `<locale>.source-hashes.generated.ts`
- * beside these bundles (maintainer ruling #12069 Option A, #11671). A record
+ * beside these bundles (maintainer ruling #12069 Option A, commit 09b4f4e4e). A record
  * says: "this locale's leaf at that path is still a byte copy of THAT source
  * revision". Recording alone changes nothing a user sees — the substitution is
  * what {@link withSourceFallback} does, and until it was wired here this set