Feature: requests that the KoishiSession class be exported in order to extend the custom method

[dragon-fish]

koishi/packages/core/src/session.ts

Line 100 in d1dade9

class KoishiSession<U, G, C> {

RT, so that we can do something like this:

declare module 'koishi' {
  interface Session {
    someAction: () => void
  }
}
KoishiSession.prototype.someAction = function() {/* ... */}

P.S. This can be done in older versions (like < 4.12) by extending the Session class, but it is now exported only as an interface.