I think the "conshine" is a typing error for "Con Shine" (which is the name of a person in the song). The name "Con" is short for the Irish name "Conleth" (or "Conláed" in Irish).

The person who transcribed the lyrics probably didn't know this. So I think "conshine" is not a proper word and is a red herring as far as this discussion is concerned.

What I don't know is whether "Con Shine" is a real person, perhaps related to the singer Brendan Shine, or whether the character was invented by the songwriter.