chore: Fix several style lints (#17488)

It's not comprehensive enough to start linting on `style` group, but
hey, it's a start.

Release Notes:

- N/A

crates/language_model/src/provider/anthropic.rs

@@ -58,7 +58,7 @@ pub struct AnthropicLanguageModelProvider {
     state: gpui::Model<State>,
 }
 
-const ANTHROPIC_API_KEY_VAR: &'static str = "ANTHROPIC_API_KEY";
+const ANTHROPIC_API_KEY_VAR: &str = "ANTHROPIC_API_KEY";
 
 pub struct State {
     api_key: Option<String>,

crates/language_model/src/provider/cloud.rs

@@ -48,7 +48,7 @@ fn zed_cloud_provider_additional_models() -> &'static [AvailableModel] {
     static ADDITIONAL_MODELS: LazyLock<Vec<AvailableModel>> = LazyLock::new(|| {
         ZED_CLOUD_PROVIDER_ADDITIONAL_MODELS_JSON
             .map(|json| serde_json::from_str(json).unwrap())
-            .unwrap_or(Vec::new())
+            .unwrap_or_default()
     });
     ADDITIONAL_MODELS.as_slice()
 }
@@ -777,12 +777,12 @@ impl LlmApiToken {
         if let Some(token) = lock.as_ref() {
             Ok(token.to_string())
         } else {
-            Self::fetch(RwLockUpgradableReadGuard::upgrade(lock).await, &client).await
+            Self::fetch(RwLockUpgradableReadGuard::upgrade(lock).await, client).await
         }
     }
 
     async fn refresh(&self, client: &Arc<Client>) -> Result<String> {
-        Self::fetch(self.0.write().await, &client).await
+        Self::fetch(self.0.write().await, client).await
     }
 
     async fn fetch<'a>(

crates/language_model/src/provider/google.rs

@@ -51,7 +51,7 @@ pub struct State {
     _subscription: Subscription,
 }
 
-const GOOGLE_AI_API_KEY_VAR: &'static str = "GOOGLE_AI_API_KEY";
+const GOOGLE_AI_API_KEY_VAR: &str = "GOOGLE_AI_API_KEY";
 
 impl State {
     fn is_authenticated(&self) -> bool {

crates/language_model/src/provider/open_ai.rs

@@ -55,7 +55,7 @@ pub struct State {
     _subscription: Subscription,
 }
 
-const OPENAI_API_KEY_VAR: &'static str = "OPENAI_API_KEY";
+const OPENAI_API_KEY_VAR: &str = "OPENAI_API_KEY";
 
 impl State {
     fn is_authenticated(&self) -> bool {

crates/language_model/src/registry.rs

@@ -176,7 +176,7 @@ impl LanguageModelRegistry {
         model_id: &LanguageModelId,
         cx: &mut ModelContext<Self>,
     ) {
-        let Some(provider) = self.provider(&provider) else {
+        let Some(provider) = self.provider(provider) else {
             return;
         };
 

crates/language_model/src/request.rs

@@ -212,7 +212,7 @@ impl LanguageModelRequestMessage {
         self.content.is_empty()
             || self
                 .content
-                .get(0)
+                .first()
                 .map(|content| match content {
                     MessageContent::Text(text) => text.trim().is_empty(),
                     MessageContent::ToolResult(tool_result) => {