* restore .gitmodules

* Revert "[TD-13408]<test>: move tests directory out"

This reverts commit 7db7bd9337cedc4cd0e3f3b16618b97d09791eaa.

* revert to make tests back

* immigrate file change in stand-alone repo to TDengine

* remove tests repository checkout
Co-authored-by: Ntangfangzhi <fztang@taosdata.com>

* remove out-dated links

* refine taostools section

* adjst descriptions

* fix typo

* fix taosBenchmark doc link

* update documentation20/cn/02.getting-started/docs.md

* [TD-13571]<docs>: fix outdated

16KB => 64KB

repair insert Timestamp is null error

Feature/td 11214

* [TD-13785]<fix>: change method for jdbc judge update or query

* [TD-13785]<fix>: add desc test case

[TS-1233]<fix>: fixed coredump when timestamp collection excessed thr…

* remove out-dated links

* refine taostools section

* adjst descriptions

* fix typo

* fix taosBenchmark doc link

* update documentation20/cn/02.getting-started/docs.md

* remove out-dated links

* refine taostools section

* adjst descriptions

* fix typo

* fix taosBenchmark doc link

Update docs.md

Update the section of performance optimization

* [TD-11008]<feature>:csharp support subscribe and add sample

* [TD-11008]<feature>:update c# subscribe sample

[TS-1285]<fix>: fix alter timestamp tag precision issue

fix time related function using taosParseTime generate random output

* [TD-13569]<feature>:csharp async query

* [TD-13569]<feature>:csharp support Async query

* [TD-13569]<feature>:remove some useless method in example util.cs

* [TD-13569]<feature>fix indent

Update docs.md

misspelling of current.