Bulk convert comments above classes/functions/methods into proper docstrings

data/sig.py

@@ -1,11 +1,13 @@
 from dataclasses import dataclass
 
-# Data class that defines a Special Interest Group.
+
 @dataclass
 class SIG:
+    """Data class that defines a Special Interest Group."""
+
     # SIG name, e.g. "POTA"
     name: str
     # Description, e.g. "Parks on the Air"
     description: str
     # Regex matcher for references, e.g. for POTA r"[A-Z]{2}\-\d+".
-    ref_regex: str = None
+    ref_regex: str = None