[v5] Add `.stateNode` for actions and guards

[davidkpiano]

The stateNode where an action or guard originates can now be read in the action or guard's provided implementation, or inline:

const machine = createMachine({
  initial: 'idle',
  states: {
    idle: {
      meta: { message: 'I am idle', enabled: true },

      entry: ({ stateNode }) => {
        stateNode.message; // 'I am idle'
      },

      on: {
        someEvent: {
          guard: ({ stateNode }) => {
            return stateNode.enabled; // true
          }
        }
      }
    }
  }
});

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🦋 Changeset detected

Latest commit: c1d81a956831fad2469fd97fce54ea759d525bbd

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
xstate	Minor

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XState React Template	Configuration

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