Theses notes are talking about common problems I find when modifying the Client and the Server.

Moves not showing for a pokemon.

This one is funny. The reason why I say its funny is because you most likely spelt a move wrong in the learnsets.ts file. This is usually the case.

Unix Socket Warnings

This happens on windows. This is not a problem, just want to list it here, but the reason why it is displaying those messages, is because windows doesn't support unix. Unix is supported by Linux. Showdown is running on a ngnix server, which you guessed it is Supported by Linux.

Pokemon is not showing changes

This is a common problem. It usually has to do with the web browser caching. At least that what it has been for me. To fix this, use the inspect tool (ctrl + shift + i) then right click on the refresh button for the web browser (this only works for chrome that I know of) then click on empty cache, and hard reload. This will clear the cache, and force a hard reload, which will implement the changes into the client/server.