Bug: `imag` is not included in rendered specification for 2022.12

As evident in the 2022.12 [table of contents](https://github.com/data-apis/array-api/blob/3d918783ac7f11cb5b31681b2badddeca81dc71e/spec/2022.12/API_specification/elementwise_functions.rst), `imag` is not present.

This was an omission in [gh-496](https://github.com/data-apis/array-api/pull/496).