correct DateOffset and Tick docstrings, add notes to v2.2.0

doc/source/whatsnew/v2.2.0.rst

@@ -584,6 +584,7 @@ Other Deprecations
 - Changed :meth:`Timedelta.resolution_string` to return ``h``, ``min``, ``s``, ``ms``, ``us``, and ``ns`` instead of ``H``, ``T``, ``S``, ``L``, ``U``, and ``N``, for compatibility with respective deprecations in frequency aliases (:issue:`52536`)
 - Deprecated :attr:`offsets.Day.delta`, :attr:`offsets.Hour.delta`, :attr:`offsets.Minute.delta`, :attr:`offsets.Second.delta`, :attr:`offsets.Milli.delta`, :attr:`offsets.Micro.delta`, :attr:`offsets.Nano.delta`, use ``pd.Timedelta(obj)`` instead (:issue:`55498`)
 - Deprecated :func:`pandas.api.types.is_interval` and :func:`pandas.api.types.is_period`, use ``isinstance(obj, pd.Interval)`` and ``isinstance(obj, pd.Period)`` instead (:issue:`55264`)
+- Deprecated :func:`pd.DateOffset().is_anchored()`, use ``DateOffset().n == 1`` instead (:issue:`55388`)
 - Deprecated :func:`pd.core.internals.api.make_block`, use public APIs instead (:issue:`40226`)
 - Deprecated :func:`read_gbq` and :meth:`DataFrame.to_gbq`. Use ``pandas_gbq.read_gbq`` and ``pandas_gbq.to_gbq`` instead https://pandas-gbq.readthedocs.io/en/latest/api.html (:issue:`55525`)
 - Deprecated :meth:`.DataFrameGroupBy.fillna` and :meth:`.SeriesGroupBy.fillna`; use :meth:`.DataFrameGroupBy.ffill`, :meth:`.DataFrameGroupBy.bfill` for forward and backward filling or :meth:`.DataFrame.fillna` to fill with a single value (or the Series equivalents) (:issue:`55718`)
@@ -592,6 +593,7 @@ Other Deprecations
 - Deprecated :meth:`Series.ravel`, the underlying array is already 1D, so ravel is not necessary (:issue:`52511`)
 - Deprecated :meth:`Series.resample` and :meth:`DataFrame.resample` with a :class:`PeriodIndex` (and the 'convention' keyword), convert to :class:`DatetimeIndex` (with ``.to_timestamp()``) before resampling instead (:issue:`53481`)
 - Deprecated :meth:`Series.view`, use :meth:`Series.astype` instead to change the dtype (:issue:`20251`)
+- Deprecated :meth:`offsets.Tick().is_anchored()`, use ``False`` instead (:issue:`55388`)
 - Deprecated ``core.internals`` members ``Block``, ``ExtensionBlock``, and ``DatetimeTZBlock``, use public APIs instead (:issue:`55139`)
 - Deprecated ``year``, ``month``, ``quarter``, ``day``, ``hour``, ``minute``, and ``second`` keywords in the :class:`PeriodIndex` constructor, use :meth:`PeriodIndex.from_fields` instead (:issue:`55960`)
 - Deprecated accepting a type as an argument in :meth:`Index.view`, call without any arguments instead (:issue:`55709`)

pandas/_libs/tslibs/offsets.pyx

@@ -756,11 +756,14 @@ cdef class BaseOffset:
         raise ValueError(f"{self} is a non-fixed frequency")
 
     def is_anchored(self) -> bool:
-        # TODO: Does this make sense for the general case?  It would help
-        # if there were a canonical docstring for what is_anchored means.
+        # GH#55388
         """
         Return boolean whether the frequency is a unit frequency (n=1).
 
+        .. deprecated:: 2.2.0
+            The is_anchored is deprecated and will be removed in a future version.
+            Do ``DateOffset().n == 1`` instead of ``DateOffset().is_anchored()``.
+
         Examples
         --------
         >>> pd.DateOffset().is_anchored()
@@ -960,6 +963,21 @@ cdef class Tick(SingleConstructorOffset):
         return True
 
     def is_anchored(self) -> bool:
+        # GH#55388
+        """
+        Return False.
+
+        .. deprecated:: 2.2.0
+            The is_anchored is deprecated and will be removed in a future version.
+            Do ``False`` instead of ``offsets.Tick().is_anchored()``.
+
+        Examples
+        --------
+        >>> pd.offsets.Tick().is_anchored()
+        False
+        >>> pd.offsets.Tick(2).is_anchored()
+        False
+        """
         warnings.warn(
             f"{type(self).__name__}.is_anchored() is deprecated and will be removed "
             f"in a future version, please use False instead.",

pandas/tests/tseries/offsets/test_fiscal.py

@@ -297,7 +297,7 @@ def test_apply(self):
 class TestFY5253LastOfMonthQuarter:
     def test_is_anchored(self):
         msg = r"FY5253Quarter.is_anchored\(\) is deprecated "
-    
+
         with tm.assert_produces_warning(FutureWarning, match=msg):
             assert makeFY5253LastOfMonthQuarter(
                 startingMonth=1, weekday=WeekDay.SAT, qtr_with_extra_week=4

pandas/tests/tseries/offsets/test_ticks.py

@@ -339,7 +339,7 @@ def test_tick_equalities(cls):
 
 @pytest.mark.parametrize("cls", tick_classes)
 def test_tick_offset(cls):
-    msg = f"{cls.__name__}.is_anchored\(\) is deprecated "
+    msg = rf"{cls.__name__}.is_anchored\(\) is deprecated "
 
     with tm.assert_produces_warning(FutureWarning, match=msg):
         assert not cls().is_anchored()