settings: Remove auxiliary Content types where possible (#16744)

Release Notes:

- N/A

crates/repl/src/jupyter_settings.rs

@@ -6,8 +6,10 @@ use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use settings::{Settings, SettingsSources};
 
-#[derive(Debug, Default)]
+#[derive(Clone, Debug, Default, Serialize, Deserialize, JsonSchema)]
+#[serde(default)]
 pub struct JupyterSettings {
+    /// Default kernels to select for each language.
     pub kernel_selections: HashMap<String, String>,
 }
 
@@ -20,26 +22,10 @@ impl JupyterSettings {
     }
 }
 
-#[derive(Clone, Serialize, Deserialize, JsonSchema, Debug)]
-pub struct JupyterSettingsContent {
-    /// Default kernels to select for each language.
-    ///
-    /// Default: `{}`
-    pub kernel_selections: Option<HashMap<String, String>>,
-}
-
-impl Default for JupyterSettingsContent {
-    fn default() -> Self {
-        JupyterSettingsContent {
-            kernel_selections: Some(HashMap::new()),
-        }
-    }
-}
-
 impl Settings for JupyterSettings {
     const KEY: Option<&'static str> = Some("jupyter");
 
-    type FileContent = JupyterSettingsContent;
+    type FileContent = Self;
 
     fn load(
         sources: SettingsSources<Self::FileContent>,
@@ -51,10 +37,8 @@ impl Settings for JupyterSettings {
         let mut settings = JupyterSettings::default();
 
         for value in sources.defaults_and_customizations() {
-            if let Some(source) = &value.kernel_selections {
-                for (k, v) in source {
-                    settings.kernel_selections.insert(k.clone(), v.clone());
-                }
+            for (k, v) in &value.kernel_selections {
+                settings.kernel_selections.insert(k.clone(), v.clone());
             }
         }