Pipeline steps doc generator is missing the `build` step

[MarkEWaite]

Describe your use-case which is not covered by existing documentation.

The Pipeline build step page has previously included a description of the build step that a Pipeline can use to run another job. That description is no longer visible in the page.

Today's page

What it should include

The page should include the online help for the build step that is available from within the Pipeline syntax snippet generator of a running Jenkins controller. On my controller, it looks like this:

Reference any relevant documentation, other materials or issues/pull requests that can be used for inspiration.

Issue first reported in the Jenkins documentation feedback sheet, row 1561.