assistant: Add Mistral support (#24879)

Closes #12519.

Release Notes:

- Added support for Mistral to the Assistant.

---------

Co-authored-by: Marshall Bowers <git@maxdeviant.com>

crates/language_models/src/language_models.rs

@@ -17,6 +17,7 @@ pub use crate::provider::cloud::RefreshLlmTokenListener;
 use crate::provider::copilot_chat::CopilotChatLanguageModelProvider;
 use crate::provider::google::GoogleLanguageModelProvider;
 use crate::provider::lmstudio::LmStudioLanguageModelProvider;
+use crate::provider::mistral::MistralLanguageModelProvider;
 use crate::provider::ollama::OllamaLanguageModelProvider;
 use crate::provider::open_ai::OpenAiLanguageModelProvider;
 pub use crate::settings::*;
@@ -64,6 +65,10 @@ fn register_language_model_providers(
         GoogleLanguageModelProvider::new(client.http_client(), cx),
         cx,
     );
+    registry.register_provider(
+        MistralLanguageModelProvider::new(client.http_client(), cx),
+        cx,
+    );
     registry.register_provider(CopilotChatLanguageModelProvider::new(cx), cx);
 
     cx.observe_flag::<feature_flags::LanguageModels, _>(move |enabled, cx| {