Tag implication: sword_of_hisou

Create implication: sword_of_hisou -> sword

I don't believe there are any alternative forms of it that would make it not a sword, so the implication seems in order.

Usually, we don't do implications of named weapons to their respective weapon types.
Sometimes, they may end up in different forms.

Examples: post #790516 and post #1059947

see forum #44850