Update bucketing.md (#601)

.jsm --> system.mjs

Author: teonbrooks

docs/deep-dives/data/bucketing.md

@@ -67,7 +67,7 @@ This example uses the Nimbus experiment format. While the Normandy format is dif
 
 Bucketing uses a stable unique identifier generated at startup. Note that this identifier is _not_ `client_id`, which is the standard unit for aggregation for most data analysis in Firefox.
 
-Desktop experiments use the `normandy_id`, a unique stable identifier generated by the `ClientEnvironment` module during first run and stored in a preference (see [implementation](https://searchfox.org/mozilla-central/source/toolkit/components/utils/ClientEnvironment.jsm#99)). It differs from `client_id` in that it is _not_ exposed to Telemetry and it is not synced across profiles / accounts.
+Desktop experiments use the `normandy_id`, a unique stable identifier generated by the `ClientEnvironment` module during first run and stored in a preference (see [implementation](https://searchfox.org/mozilla-central/source/toolkit/components/utils/ClientEnvironment.sys.mjs#99)). It differs from `client_id` in that it is _not_ exposed to Telemetry and it is not synced across profiles / accounts.
 
 Mobile experiments use the `nimbus_id`, a unique identifier generated by the Nimbus client during first run stored in the experiments database (see [implementation](https://github.com/mozilla/application-services/blob/866c72cddc4d925a0dc1a83c9aeebd2e878be85e/components/nimbus/src/lib.rs#L433)).