Fix Rust CI: format E2E imports and skip the README fragment

The Auto tier README example is a fragment that references an undefined
'session' binding, so rustdoc could not compile it as a doctest. Mark it
'rust,ignore' to match every other fragment in the file, and apply the
rustfmt import merge the format job asked for.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 2aad36e9-e078-4b9c-afa1-0c7cd2c71f74

Author: andyfeller

rust/README.md

@@ -390,7 +390,7 @@ Change the Auto routing preference without changing the selected model. The runt
 
 Watch for the outcome through the `session.model_change` event on success or the ephemeral `session.auto_tier_switch_failed` event on failure. Read the authoritative committed, pending, and activating preferences at any time through the session's `model.getCurrent` RPC method.
 
-```rust
+```rust,ignore
 use github_copilot_sdk::{AutoTier, ModelSwitchAutoTierStatus};
 
 let result = session.set_auto_tier(Some(AutoTier::Intelligence)).await?;

rust/tests/e2e/auto_tier.rs

@@ -1,7 +1,7 @@
+use github_copilot_sdk::SetModelOptions;
 use github_copilot_sdk::rpc::ModelSwitchAutoTierStatus;
 use github_copilot_sdk::session::Session;
 use github_copilot_sdk::session_events::AutoTier;
-use github_copilot_sdk::SetModelOptions;
 
 use super::support::with_dedicated_e2e_context;