Update references to 'serverpod generate' to reflect the changes with hot reload

[Swiftaxe]

There are 75 mentions of the command 'serverpod generate' in the docs folder. Update these to reflect the changes with hot reload.

The goal is for the docs to reflect the new way of working with hot reload; however, it is still possible to run 'serverpod generate' manually, and this has to be taken into consideration.