silence ipython warning

Author: MarcoGorelli

doc/source/user_guide/timeseries.rst

@@ -360,6 +360,7 @@ as timezone-naive timestamps and then localize to the appropriate timezone:
    types (e.g. an int64).
 
    .. ipython:: python
+      :okwarning:
 
       pd.to_datetime([1490195805.433, 1490195805.433502912], unit="s")
       pd.to_datetime(1490195805433502912, unit="ns")
@@ -513,6 +514,7 @@ Since pandas represents timestamps in nanosecond resolution, the time span that
 can be represented using a 64-bit integer is limited to approximately 584 years:
 
 .. ipython:: python
+   :okwarning:
 
    pd.Timestamp.min
    pd.Timestamp.max