ref(rust): standardize client init guard name (#14463)

Author: lcian

docs/platforms/rust/common/tracing/instrumentation/automatic-instrumentation.mdx

@@ -24,7 +24,7 @@ fn main() {
         .with(sentry::integrations::tracing::layer())
         .init();
 
-    let _sentry = sentry::init(sentry::ClientOptions {
+    let _guard = sentry::init(sentry::ClientOptions {
         release: sentry::release_name!(),
         traces_sample_rate: 1.0,
         // Capture user IPs and potentially sensitive headers when using HTTP server integrations
@@ -55,7 +55,7 @@ The Rust SDK offers an integration for the OpenTelemetry ecosystem.
 The integration can automatically capture Sentry [spans/transactions](/concepts/key-terms/tracing/distributed-tracing/#traces-transactions-and-spans) for every span created through the OpenTelemetry API, with support for [distributed tracing](/concepts/key-terms/tracing/distributed-tracing/).
 The integration also captures errors with the correct span and trace associations.
 
-For this integration to work as intended, only the OpenTelemetry tracing API should be used to manage spans. 
+For this integration to work as intended, only the OpenTelemetry tracing API should be used to manage spans.
 Mixing it with the Sentry tracing API will result in incorrectly nested spans.
 
 To get started using the OpenTelemetry integration for the Sentry Rust SDK, add the necessary dependencies to your `Cargo.toml`:

platform-includes/configuration/sample-rate/rust.mdx

@@ -1,5 +1,5 @@
 ```rust
-let _sentry = sentry::init(sentry::ClientOptions {
+let _guard = sentry::init(sentry::ClientOptions {
     sample_rate: 1.0,
     ..Default::default()
 });

platform-includes/performance/configure-sample-rate/rust.mdx

@@ -1,5 +1,5 @@
 ```rust
-let _sentry = sentry::init(sentry::ClientOptions {
+let _guard = sentry::init(sentry::ClientOptions {
     release: sentry::release_name!(),
     // To set a uniform sample rate
     traces_sample_rate: 0.2,

platform-includes/performance/traces-sample-rate/rust.mdx

@@ -1,5 +1,5 @@
 ```rust
-let _sentry = sentry::init(sentry::ClientOptions {
+let _guard = sentry::init(sentry::ClientOptions {
     release: sentry::release_name!(),
     traces_sample_rate: 1.0,
     ..Default::default()