enhance documentation for Registry class usage and its singleton pattern

fastkml/registry.py

@@ -20,6 +20,14 @@
 This approach allows for flexible, declarative mapping between XML and Python objects,
 with the registry acting as a central configuration for these mappings.
 
+Direct ``Registry`` class use is typically only for library internals or advanced
+customization. For normal usage, stick with the ``registry`` instance:
+
+- The library is designed around this global instance.
+- Ensures all parts of the library use the same registry.
+- Pre-populated with standard KML mappings.
+- Singleton pattern: Avoids multiple conflicting registries.
+
 """
 
 from dataclasses import dataclass
@@ -116,14 +124,6 @@ class Registry:
     - Enable consistent handling of attributes across different KML classes.
     - Facilitate extensibility and maintainability of the library.
 
-    Direct ``Registry`` class use is typically only for library internals or advanced
-    customization. For normal usage, stick with the ``registry`` instance:
-
-    - The library is designed around this global instance.
-    - Ensures all parts of the library use the same registry.
-    - Pre-populated with standard KML mappings.
-    - Singleton pattern: Avoids multiple conflicting registries.
-
     """
 
     _registry: Dict[Type["_XMLObject"], List[RegistryItem]]