* Fix high-freq data name from `yahoo_cn_1min` to `cn_data_1min`
* re-format example data names using `qlib_{region}_{feq}`, e.g. qlib_cn_1d
* re-format example data names using `{region}_{feq}`, e.g. us_1d and cn_1min
* keep using for 1day data, and change 1min data to
* updated readme of yahoo collector where region parameter was incorrect
* changes
update readme of yahoo collector where region parameter was incorrect
* update readme of yahoo collector
update readme of yahoo collector where region parameter was incorrect
* updated changes
* updated readme of cn1d data
Co-authored-by: Gaurav Chauhan01/HO/Analytics/General <Gaurav.Chauhan01@bajajallianz.in>