The tag alias #56192 ah_my_goddess! -> oh_my_goddess! has been approved.

Reason: ah_my_goddess! is the Englsih relase name. oh_my_goddess! is an alternative Japanese name.

EDIT: The tag alias ah_my_goddess! -> oh_my_goddess! (forum #324748) has been approved by @bitWolfy.

If ah_my_goddess! Is the English title we should be going with that

+1 per MatrixMash's below post

The manga has apparently been released in English under both names by various publishers.

Pros:
Wikipedia uses Oh_My_Goddess! as the canonical name, and redirects from https://en.wikipedia.org/wiki/Ah!_My_Goddess.
In the section on the title discrepancy, there is a quote from the manga author: "Fujishima stated in Animerica that "Oh" was closer to his intent, but acknowledged that the title should be rendered so as to make sense within the country that it is published..."
If I am reading the Wikipedia article right, the earliest English release was titled Oh My Goddess! by Dark Horse.
oh_my_goddess! is currently the most tagged here on e621.
Of the two Fandom wikis, the seemingly larger one uses "Oh My Goddess". That is, ohmygoddess has a lot more links on it that ah-my-goddess although they both look inactive.

Cons:
The TvTropes article uses Ah! My Goddess.

The tag alias ah_my_goddess! -> oh_my_goddess! (forum #324748) has been approved by @bitWolfy.