chore(examples): Document conditional

[covracer]

Related issue

Fixes #2915

Description

Folks using CDKTF will benefit from an example of Fn.conditional(). Since the example necessarily calls two Token methods, also show the example there. While in functions.py, tidy up spacing.

Checklist

• I have updated the PR title to match CDKTF's style guide
• I have run the linter on my code locally
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation if applicable
• My changes generate no new warnings

yarn pretest
[...]
✖ 361 problems (0 errors, 361 warnings)

just like https://github.com/hashicorp/terraform-cdk/actions/runs/15299049553/job/43034878538#step:5:539

• I have added tests that prove my fix is effective or that my feature works if applicable Example code already covered, and I could get those tests to run
• New and existing unit tests pass locally with my changes I couldn't get the full test suite to run on the older laptop I was using for open source development; can we use the results from GitHub Actions instead?

[covracer]

@mutahhir please take a look