DOC PR09 Add "." on to_hdf format parameter
- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [ ] whatsnew entry

From #28602:
```
pandas.Series.to_hdf: Parameter "format" description should finish with "."
pandas.DataFrame.to_hdf: Parameter "format" description should finish with "."
```
@MarcoGorelli From what I've seen, these are all done:

```
pandas.read_excel: Parameter "usecols" description should finish with "."
pandas.read_sql: Parameter "con" description should finish with "."
pandas.DataFrame.corr: Parameter "method" description should finish with "."
pandas.Series.to_sql: Parameter "con" description should finish with "."
pandas.DataFrame.to_sql: Parameter "con" description should finish with "."
pandas.io.formats.style.Styler: Parameter "na_rep" description should finish with "."
pandas.io.formats.style.Styler.format: Parameter "formatter" description should finish with "."
pandas.io.formats.style.Styler.format: Parameter "na_rep" description should finish with "."
```

Cannot speak for the rest.

```
pandas.testing.assert_categorical_equal: Parameter "check_dtype" description should finish with "."
pandas.testing.assert_categorical_equal: Parameter "obj" description should finish with "."
pandas.testing.assert_extension_array_equal: Parameter "left" description should finish with "."
pandas.testing.assert_extension_array_equal: Parameter "right" description should finish with "."
pandas.testing.assert_interval_array_equal: Parameter "obj" description should finish with "."
pandas.testing.assert_sp_array_equal: Parameter "check_fill_value" description should finish with "."
pandas.eval: Parameter "truediv" description should finish with "."
pandas.PeriodIndex: Parameter "freq" description should finish with "."
pandas.core.window.rolling.Rolling.apply: Parameter "engine" description should finish with "."
pandas.core.window.rolling.Rolling.apply: Parameter "engine_kwargs" description should finish with "."
pandas.core.window.expanding.Expanding.apply: Parameter "engine" description should finish with "."
pandas.core.window.expanding.Expanding.apply: Parameter "engine_kwargs" description should finish with "."
pandas.core.groupby.DataFrameGroupBy.corr: Parameter "method" description should finish with "."
``` cool, feel free to any of the remaining ones if you want