Add remaining docstrings to complete documentation coverage

Co-authored-by: varun-r-mallya <100590632+varun-r-mallya@users.noreply.github.com>

pythonbpf/maps/maps_pass.py

@@ -43,6 +43,7 @@ def is_map(func_node):
 
 
 class BPFMapType(Enum):
+    """Enumeration of BPF map types."""
     UNSPEC = 0
     HASH = 1
     ARRAY = 2

pythonbpf/maps/maps_utils.py

@@ -1,3 +1,5 @@
+"""Registry for BPF map processor functions."""
+
 from collections.abc import Callable
 from typing import Any
 
@@ -12,6 +14,7 @@ class MapProcessorRegistry:
         """Decorator to register a processor function for a map type"""
 
         def decorator(func):
+            """Decorator that registers the processor function."""
             cls._processors[map_type_name] = func
             return func