The bulk update request #11241 has been approved by @nonamethanks.
create alias halter_top -> halterneck
Technically, according to the wiki, halter top is supposed to be for halterneck shirts. Of course, given the tag's name, it's instead used for any kind of halter tops (for example halter_top bikini has 9k posts).
Given that halternecks by definition apply to the top, it's a useless tag. At best it'd be used for halterneck -dress, but that search has 3 times the results of halter_top.
Even if we interpret the wiki's words as allowing bikini, it's still a pointless tag, because someone still has to add bikini or another article of clothing to their search to be able to search for specific kinds of halternecks, so the only thing that changes between bikini halterneck and bikini halter_top is that the first search returns three times the results.