docs: Add return descriptions to Series's abs, alias, all, `any…

…` methods for clarity (#1653)

docs: Add return descriptions to Series `abs`, `alias`, `all`, 'any' methods for clarity

narwhals/series.py

@@ -843,6 +843,9 @@ def any(self) -> Any:
         Notes:
           Only works on Series of data type Boolean.
 
+        Returns:
+            A boolean indicating if any values in the Series are True.
+
         Examples:
             >>> import pandas as pd
             >>> import polars as pl
@@ -870,6 +873,9 @@ def any(self) -> Any:
     def all(self) -> Any:
         """Return whether all values in the Series are True.
 
+        Returns:
+            A boolean indicating if all values in the Series are True.
+
         Examples:
             >>> import pandas as pd
             >>> import polars as pl
@@ -1334,6 +1340,9 @@ def drop_nulls(self) -> Self:
     def abs(self) -> Self:
         """Calculate the absolute value of each element.
 
+        Returns:
+            A new Series with the absolute values of the original elements.
+
         Examples:
             >>> import pandas as pd
             >>> import polars as pl
@@ -1631,6 +1640,9 @@ def alias(self, name: str) -> Self:
         Arguments:
             name: The new name.
 
+        Returns:
+            A new Series with the updated name.
+
         Examples:
             >>> import pandas as pd
             >>> import polars as pl