fix typo and add more types

Author: artcz

intbot/core/analysis/products.py

@@ -11,7 +11,7 @@
 
 
 class LocalisedFieldsMixin:
-    # Marking as ClassVar here is importnat. It doens't work without it :)
+    # Marking as ClassVar here is important. It doens't work without it :)
     _localised_fields: ClassVar[Iterable[str]] = ()
 
     @model_validator(mode="before")
@@ -104,7 +104,7 @@ def flat_product_data(products: list[Product]) -> pl.DataFrame:
     return pl.DataFrame(rows)
 
 
-def latest_flat_product_data():
+def latest_flat_product_data() -> pl.DataFrame:
     """
     Thin wrapper on getting latest information from the database, and
     converting into a polars data frame