DEPR: correct locations to access public tslib objects (pandas-dev#15897)

Author: jorisvandenbossche

pandas/__init__.py

@@ -64,7 +64,11 @@
 parser = _DeprecatedModule(deprmod='pandas.parser', deprmodto='pandas.io.libparsers')
 lib = _DeprecatedModule(deprmod='pandas.lib', deprmodto='pandas._libs.lib',
                         moved={'infer_dtype': 'pandas.api.lib.infer_dtype'})
-tslib = _DeprecatedModule(deprmod='pandas.tslib', deprmodto='pandas._libs.tslib')
+tslib = _DeprecatedModule(deprmod='pandas.tslib', deprmodto='pandas._libs.tslib',
+                          moved={'Timestamp': 'pandas.Timestamp',
+                                 'Timedelta': 'pandas.Timedelta',
+                                 'NaT': 'pandas.NaT',
+                                 'OutOfBoundsDatetime': 'pandas.errors.OutOfBoundsDatetime'})
 
 # use the closest tagged version if possible
 from ._version import get_versions