Learn English – What’s the word for a picture that is turned over – is it opposite

This is an example of lingo

lingo : b : the special vocabulary of a particular field of interest

Here "code complete" indicates a stage or milestone in the software development lifecycle.

As is the case with all specialized vocabulary it should be used only with an audience who is expected to be able to understand it.

In this particular case, the usage is quite informal and to maintain the same register I'd suggest using contractions and I'd probably still use scare quotes around it:

I'm already working on it and it's almost "code complete".

Otherwise in a more formal setting, something like:

This work has already been started and coding is nearly complete.

might be better.

What is the reason?

Are you trying to introduce the reader to an argument or trying to hold the reader's interest?

Academic papers often need to let the reader know what is going to be said. Otherwise the reader will likely stop reading since the paper will seem irrelevant to them. Sentences that list some topics then end with a "... will be discussed." are fairly common.

Possibly you trying to introduce an argument into the paper. In this case it would be more natural to simply state what you want, without any details about how more will be discussed. The reader will expect justification in the following paragraphs.

Straight answer

These words can be used as part of an opposite meaning: below; ensuing, following, subsequent, succeeding

"The presidential agenda will be discussed below"

"The following evidence will convince the jury beyond a reasonable doubt that my defendant is innocent of all charges."

"The proposed hypothesis will be substantiated by the subsequent details."

"Despite the compelling nature of this argument, the succeeding details provide an alternative explanation."