Allow comments in annotations

One of the main uses for annotations as I see it is to allow devs to add comments to fields, indicating what they mean, where they're used, etc. The current implementation does not allow this. I've made a fairly large change which allows dev comments to be added. Comments must begin with a double hash ## and must be immediately following the field they are commenting on. Even when annotate is run again, the comments should remain attached to those fields.