Get diagnostics view almost building in the zed2 world

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

crates/diagnostics2/src/project_diagnostics_settings.rs

@@ -0,0 +1,28 @@
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+#[derive(Deserialize, Debug)]
+pub struct ProjectDiagnosticsSettings {
+    pub include_warnings: bool,
+}
+
+#[derive(Clone, Default, Serialize, Deserialize, JsonSchema, Debug)]
+pub struct ProjectDiagnosticsSettingsContent {
+    include_warnings: Option<bool>,
+}
+
+impl settings::Settings for ProjectDiagnosticsSettings {
+    const KEY: Option<&'static str> = Some("diagnostics");
+    type FileContent = ProjectDiagnosticsSettingsContent;
+
+    fn load(
+        default_value: &Self::FileContent,
+        user_values: &[&Self::FileContent],
+        _cx: &mut gpui::AppContext,
+    ) -> anyhow::Result<Self>
+    where
+        Self: Sized,
+    {
+        Self::load_via_json_merge(default_value, user_values)
+    }
+}