agent: Update pieces of copy in the settings view (#35621)

Some tiny updates to make the agent panel's copywriting sharper.

Release Notes:

- N/A

crates/language_models/src/provider/open_ai_compatible.rs

@@ -466,7 +466,7 @@ impl Render for ConfigurationView {
         let api_key_section = if self.should_render_editor(cx) {
             v_flex()
                 .on_action(cx.listener(Self::save_api_key))
-                .child(Label::new("To use Zed's assistant with an OpenAI compatible provider, you need to add an API key."))
+                .child(Label::new("To use Zed's agent with an OpenAI-compatible provider, you need to add an API key."))
                 .child(
                     div()
                         .pt(DynamicSpacing::Base04.rems(cx))