DOC: fix punctuation in Timestamp/Timedelta docstrings
- [ ] xref #27977
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Add periods to Timestamp and Timedelta doctrings for the following attributes and methods:
```
pandas.Timestamp.resolution
pandas.Timestamp.tz
pandas.Timestamp.ceil
pandas.Timestamp.combine
pandas.Timestamp.floor
pandas.Timestamp.fromordinal
pandas.Timestamp.replace
pandas.Timestamp.round
pandas.Timestamp.weekday
pandas.Timedelta.ceil
pandas.Timedelta.floor
pandas.Timedelta.isoformat
pandas.Timedelta.round
```

I did not find the method for `pandas.Timestamp.isoweekday` this in the Timestamp source code. Was this deprecated ? @datapythonista 