[rust] Docs update: use `run_gnrt.py` for detecting available updates.

Bug: None
Change-Id: Ic0967a71b7c5c7286830fbe10dc89edebf9e11f6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6648846
Commit-Queue: Manish Goregaokar <[email protected]>
Reviewed-by: Manish Goregaokar <[email protected]>
Auto-Submit: Ɓukasz Anforowicz <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1474459}
NOKEYCHECK=True
GitOrigin-RevId: fcd32e202005380d9c00f97019345f937a8503ee
diff --git a/crates/create_update_cl.md b/crates/create_update_cl.md
index a76abeb..29d1dd9 100644
--- a/crates/create_update_cl.md
+++ b/crates/create_update_cl.md
@@ -114,7 +114,7 @@
 updates):
 
 ```sh
-$ tools/crates/run_cargo.py -Zunstable-options -C third_party/rust/chromium_crates_io -Zbindeps update --dry-run --verbose
+$ tools/crates/run_gnrt.py update -- --verbose --dry-run
 ...
    Unchanged serde_json_lenient v0.1.8 (latest: v0.2.0)
    Unchanged syn v1.0.109 (latest: v2.0.53)