Consider updating the tags format

QQEM contains special tags like "//nodes", "//main" etc. The format of these nodes have 2 potential issues:

1. As they are standard comments, user might not understand that they are special and modify/remove them.
2. User might write comment which accidentally matches to a tag. For example "//nodes are nice" or "//main meaning of this..."

So consider making tags more unique. Ideas: "//#main", "//@main" or not being comments "#main", "@main".