### _Why are the changes needed?_
<!--
Please clarify why the changes are needed. For instance,
1. If you add a feature, you can talk about the use case of it.
2. If you fix a bug, you can clarify why it is a bug.
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At now, we have already remove the active/standby faileover mode
type code.
### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible
- [ ] Add screenshots for manual tests if appropriate
- [ ] [Run test](https://kyuubi.readthedocs.io/en/latest/tools/testing.html#running-tests) locally before make a pull request
Closes#650 from Peng-Lei/fix_doc.
Closes#650
caada9a [PengLei] Remove the active/standby Failover mode type
Authored-by: PengLei <18066542445@189.cn>
Signed-off-by: Kent Yao <yao@apache.org>
24e8f7b639