feature request: support yaml multiline format

[madfr-at-vipps]

Steps to recreate

• Given any input dotnet swagger tofile --output docs/swagger.yaml --yaml where a property has newlines. For example.

  /// <summary>
  /// This should look
  /// like this in the output
  /// </summary>

Result

A yaml file where the summary is rendered like so.

'This should look\r\nlike this in the output'

Expected

A yaml output in multiline format

summary: |
  This should look
  like this

Background

In my company we have some non-developers that's very active in working with the actual swagger file. Even though the generated output looks just fine rendered, for code reviews and manual file changes a multiline format is much easier to work with.

[Havunen]

Pipelining some external beautifier program is probably easiest for now. I couldn't find a public option to produce non-minified output

[madfr-at-vipps]

Yeah. That's what we ended up doing.