How to define a list of offenses?

[QuentinMcCarthy]

I'm trying to create a linter for a fork of Inform 7 (.i7x) files and this Linter is the first and foremost linter I see in VSCode.
There already exists a linter that was created for Atom, and what my goal essentially is is to port that old Linter into VSCode.

However, I'm having issues with the documentation; https://github.com/fnando/vscode-linter/blob/main/docs/creating-linters.md
It defines how to create the Linter extension, how to get it all working, but in the section "Defining the list of offenses", I can't figure out where it says how to define the offense list? It's got the instructions for the functions there, what the functions do so on so forth, but then it jumps ahead to "now it's going to tell you there's a semicolon missing" without saying how it knows there's a semicolon missing? How is that a defined offense?

Essentially, I need the linter to be able to recognise certain things for Inform 7 such as "if Player consents:" or "if strength of Player < 10" or so on so forth. Inform syntax for it to fix or inform the coder what's wrong, but I've no idea where to define that.