feat(python): Stabilize methods/functions (#20850)

Author: ritchie46

py-polars/polars/dataframe/frame.py

@@ -8808,9 +8808,9 @@ def unpivot(
 
         return self._from_pydf(self._df.unpivot(on, index, value_name, variable_name))
 
-    @unstable()
     def unstack(
         self,
+        *,
         step: int,
         how: UnstackDirection = "vertical",
         columns: ColumnNameOrSelector | Sequence[ColumnNameOrSelector] | None = None,
@@ -8819,10 +8819,6 @@ def unstack(
         """
         Unstack a long table to a wide form without doing an aggregation.
 
-        .. warning::
-            This functionality is considered **unstable**. It may be changed
-            at any point without it being considered a breaking change.
-
         This can be much faster than a pivot, because it can skip the grouping phase.
 
         Parameters

py-polars/polars/expr/datetime.py

@@ -8,7 +8,6 @@
 from polars._utils.convert import parse_as_duration_string
 from polars._utils.deprecation import deprecate_function, deprecate_nonkeyword_arguments
 from polars._utils.parse import parse_into_expression, parse_into_list_of_expressions
-from polars._utils.unstable import unstable
 from polars._utils.wrap import wrap_expr
 from polars.datatypes import DTYPE_TEMPORAL_UNITS, Date, Int32
 
@@ -280,15 +279,10 @@ def truncate(self, every: str | dt.timedelta | Expr) -> Expr:
         every = parse_into_expression(every, str_as_lit=True)
         return wrap_expr(self._pyexpr.dt_truncate(every))
 
-    @unstable()
     def round(self, every: str | dt.timedelta | IntoExprColumn) -> Expr:
         """
         Divide the date/datetime range into buckets.
 
-        .. warning::
-            This functionality is considered **unstable**. It may be changed
-            at any point without it being considered a breaking change.
-
         - Each date/datetime in the first half of the interval
           is mapped to the start of its bucket.
         - Each date/datetime in the second half of the interval