DEV: Improves Error msg when constructing a Timedelta (#54098)

* fix message

* lang

* v2 lang and docs

* drop doc update

Author: mcgeestocks

pandas/_libs/tslibs/timedeltas.pyx

@@ -1843,7 +1843,10 @@ class Timedelta(_Timedelta):
                              NPY_DATETIMEUNIT.NPY_FR_W,
                              NPY_DATETIMEUNIT.NPY_FR_GENERIC]):
                 err = npy_unit_to_abbrev(reso)
-                raise ValueError(f" cannot construct a Timedelta from a unit {err}")
+                raise ValueError(
+                    f"Unit {err} is not supported. "
+                    "Only unambiguous timedelta values durations are supported. "
+                    "Allowed units are 'W', 'D', 'h', 'm', 's', 'ms', 'us', 'ns'")
 
             new_reso = get_supported_reso(reso)
             if reso != NPY_DATETIMEUNIT.NPY_FR_GENERIC:

pandas/tests/tslibs/test_timedeltas.py

@@ -76,7 +76,10 @@ def test_delta_to_nanoseconds_td64_MY_raises():
 def test_unsupported_td64_unit_raises(unit):
     # GH 52806
     with pytest.raises(
-        ValueError, match=f"cannot construct a Timedelta from a unit {unit}"
+        ValueError,
+        match=f"Unit {unit} is not supported. "
+        "Only unambiguous timedelta values durations are supported. "
+        "Allowed units are 'W', 'D', 'h', 'm', 's', 'ms', 'us', 'ns'",
     ):
         Timedelta(np.timedelta64(1, unit))