doc: document key encryption options

[tniessen]

There is very little documentation on the supported encryption options. This should be enough for most use cases.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• documentation is changed or added
• commit message follows commit guidelines

[nodejs-github-bot]

@tniessen build started: https://ci.nodejs.org/blue/organizations/jenkins/node-test-pull-request-lite-pipeline/detail/node-test-pull-request-lite-pipeline/1220/pipeline

[thefourtheye]

/ping @nodejs/crypto

[bnoordhuis]

@tniessen Do you plan to follow up? This looks good to go once you incorporate the review feedback.

[tniessen]

@nodejs/crypto @nodejs/documentation PTAL.

[sam-github]

Text is informative, and LGTM. I leave it to you to decide to address (or not) the comment on duplicate docs.

[tniessen]

Thanks for reviewing and sorry about the long delay, I figured it made sense to wait until the key object API had been finalized. That also took care of the duplication you were worried about, @sam-github. I didn't change the text itself, I just moved it to keyObject.export.

[tniessen]

Landed in 345d3f3, thanks for reviewing!