Wrong specification for the addtag input

[Zeli0]

According to the Notes on command format, square brackets with ellipsis denotes a field that can be included any number of times, including 0 times.

However, despite the tag fields for addtag being specified with this format, the actual addtag format does not allow 0 tags as an acceptable input.

[nus-pe-bot]

Your response not required for this bug as the team has accepted the bug as it is.