"I noticed an (minor) imperfection in my paper, but it is already under review. What should I do now? [duplicate]

I submitted a paper to a journal early last year that was given major corrections. The reviewers were generally positive about the contribution but felt the technical framework needed simplified.

I spent 6 months or so on the corrections and sent it back a couple of weeks ago. The journal secretary has since confirmed it's back with the reviewers.

I've since noticed there's something missing from the paper and although it's relatively trivial - insofar as it doesn't affect the results - I'm concerned that it will ruin my chances of acceptance.

Basically, in the revised paper I simplified the framework by binning multiple confusing definitions in favour of four new definitions of four similar concepts (let's call then apple, orange, banana and pear, with the definitions being "X is a(n) {apple,orange,banana,pear} if such-and-such a property holds"). These definitions are all in the paper as resubmitted.

Each of these concepts then has an associated definition (also new in the revised paper) of an operator whose output is a collection of each individual concept.

e.g. +(A,B) = {apple1,apple2,...,appleN}; -(A,B) = {orange1,orange2,...,orangeN} etc.

These definitions are near-identical: "the apple operation +(A,B) yields a set where every element is an apple", "the orange operation -(A,B) yields a set where every element is an orange" etc.

(I've trivialised the definitions but you hopefully get the idea).

My problem is that I've only provided definitions of the operators for apples and oranges and completely forgot the ones for bananas and pears. I subsequently say something along the lines of "consider the following banana operation *(A,B)..." and also later in the paper use the undefined operators in a theorem.

The definitions of banana and pear operator are near-identical to those for apple and orange, something I think is easy to deduce in context.

A silly mistake I know, but not only did I not spot it, amazingly two others I asked to review it (one internal one external) didn't spot it either.

I'm just wondering if it's worth worrying about? I suppose it's likely that the reviewers won't spot it either, but if they do, does this seem like a minor correction (rest of the paper notwithstanding)? And if so, are minor corrections normally allowed after major corrections?

Edited to add: I realise that the question in the title didn't fully encapsulate what I was asking. I've updated the title to more fully reflect the question I was asking.