redis study notes total

<1> redis official website of relevant documents to learn: https://www.cnblogs.com/christmad/p/11510729.html

<2> redis internal data structures: https://www.cnblogs.com/christmad/p/11364372.html

<3> Other Redis (may be deployed, such as practical operation aspect Redis API, third-party API, etc.) to be continue ......