Previously, the examples in the `cli-builder` guide were hard-coded.
This made it impossible to test them and verify they are correct.
This commit fixes this by converting them into a proper mini-app. In a
subsequent commit, tests will be added to verify that the source code
works as expected (and guard against regressions).
Fixes#34314
PR Close#34362
The `format` attribute is an artifact of an old version of the docs
tooling (before moving it into the angular/angular repo) and no longer
does anything. People are still copy-pasting it from existing examples.
This commit removes all occurrences of the `format` attribute on code
examples.
PR Close#31674