Please define errors

[hallyn]

In https://github.com/google/goexpect/blob/master/expect.go#L840 and https://github.com/google/goexpect/blob/master/expect.go#L1224 you return a locally defined error. It would be great if you would define that error as an exported variable so that callers could more cleanly check for it.

[GrimAnEye]

Поддерживаю. Периодически возникает непонятная ошибка, а почему - неизвестно https://github.com/google/goexpect/blob/master/expect.go#L1348