DEPR: Improve commenting around two deprecations

Author: rhshadrach

pandas/_libs/tslibs/period.pyx

@@ -3018,7 +3018,7 @@ class Period(_Period):
             # GH#53446
             import warnings
 
-            # TODO: Enforce in 3.0 (#53511)
+            # TODO: Need to find an alternative before this deprecation can be enforced (#53511)
             from pandas.util._exceptions import find_stack_level
             warnings.warn(
                 "Period with BDay freq is deprecated and will be removed "

pandas/core/generic.py

@@ -9136,7 +9136,8 @@ def resample(
         from pandas.core.resample import get_resampler
 
         if convention is not lib.no_default:
-            # TODO: Enforce in 3.0 (#55968)
+            # TODO: Plan to fix resampling with PeriodIndex instead (#55968)
+            # see https://github.com/pandas-dev/pandas/pull/62270#issuecomment-3262411892
             warnings.warn(
                 f"The 'convention' keyword in {type(self).__name__}.resample is "
                 "deprecated and will be removed in a future version. "

pandas/core/resample.py

@@ -1945,7 +1945,8 @@ class PeriodIndexResampler(DatetimeIndexResampler):
 
     @property
     def _resampler_for_grouping(self):
-        # TODO: Enforce in 3.0 (#55968)
+        # TODO: Plan to fix resampling with PeriodIndex instead (#55968)
+        # see https://github.com/pandas-dev/pandas/pull/62270#issuecomment-3262411892
         warnings.warn(
             "Resampling a groupby with a PeriodIndex is deprecated. "
             "Cast to DatetimeIndex before resampling instead.",

pandas/tests/resample/test_base.py

@@ -473,6 +473,7 @@ def test_resample_empty_dtypes(index, dtype, resample_method):
     warn = None
     if isinstance(index, PeriodIndex):
         # GH#53511
+        # TODO: Need to find an alternative before this deprecation can be enforced
         index = PeriodIndex([], freq="B", name=index.name)
         warn = FutureWarning
     msg = "Resampling with a PeriodIndex is deprecated"