models: add docstring to constructor function

src/teilchensammler_cli/models.py

@@ -25,6 +25,15 @@ class Teilchen(TeilchenCreate, table=True):
 
 
 async def make_teilchen_input(text: str) -> TeilchenCreate | None:
+    """Constructor to create new Teilchen from user input.
+
+    Args:
+        text: The whole input string as provided by the user.
+
+    Returns:
+        Returns new Teilchen instance if enough parts could be extracted.
+        Returns `None` otherwise.
+    """
     import re
     from natsort import natsorted