Don't clobber other schema fields when attaching references (#15336)

This PR fixes an issue where we would clobber the other JSON Schema
fields for any field that we attached a reference to.

This resulted in these fields (e.g., `buffer_font_family`,
`ui_font_family`) losing things like their descriptions.

The approach has been adjusted that references are now added in an
additive fashion, rather than overriding the entire schema object.

Release Notes:

- Fixed an issue where font-related settings in `settings.json` were
missing their descriptions.

crates/theme/src/settings.rs

@@ -649,30 +649,30 @@ impl settings::Settings for ThemeSettings {
             ("FontFallbacks".into(), font_fallback_schema.into()),
         ]);
 
-        root_schema
+        // The list of properties that should reference another definition in
-            .schema
+        // the schema.
-            .object
+        let properties_with_references = vec![
-            .as_mut()
+            ("buffer_font_family", "#/definitions/FontFamilies"),
-            .unwrap()
+            ("buffer_font_fallbacks", "#/definitions/FontFallbacks"),
-            .properties
+            ("ui_font_family", "#/definitions/FontFamilies"),
-            .extend([
+            ("ui_font_fallbacks", "#/definitions/FontFallbacks"),
-                (
+        ];
-                    "buffer_font_family".to_owned(),
+
-                    Schema::new_ref("#/definitions/FontFamilies".into()),
+        for (property, definition) in properties_with_references {
-                ),
+            let Some(schema) = root_schema.schema.object().properties.get_mut(property) else {
-                (
+                log::warn!("property '{property}' not found in JSON schema");
-                    "buffer_font_fallbacks".to_owned(),
+                continue;
-                    Schema::new_ref("#/definitions/FontFallbacks".into()),
+            };
-                ),
+
-                (
+            match schema {
-                    "ui_font_family".to_owned(),
+                Schema::Object(schema) => {
-                    Schema::new_ref("#/definitions/FontFamilies".into()),
+                    schema.reference = Some(definition.into());
-                ),
+                }
-                (
+                Schema::Bool(_) => {
-                    "ui_font_fallbacks".to_owned(),
+                    // Boolean schemas can't have references.
-                    Schema::new_ref("#/definitions/FontFallbacks".into()),
+                }
-                ),
+            }
-            ]);
+        }
 
         root_schema
     }