Add msgstake_flow.md

[msmania]

No description provided.

[reviewpad]

AI-Generated Summary: This pull request adds a new file msgstake_flow.md to the doc/specs directory. The file contains a flowchart illustrating how a MsgStake is handled by key functions when changing a staked node's output address. It describes the rules and conditions for a transaction to be accepted or rejected by the blockchain.

[reviewpad]

AI-Generated Summary: This pull request introduces a new document, msgstake_flow.md, to the repository. The document describes the journey of changing a node's output address and outlines the different functions, validations, and key steps involved in the process. It includes illustrations in the form of flowcharts to provide a better understanding of the whole procedure.

[Olshansk]

THIS IS SO GOOD!!! 🙏 🙏 🙏 🙏

[msmania]

I feel this is an excessive effort, but yeah, it looks much better and hopefully this helps someone. Thank you for your thorough review as always!