Formatter should not squash multiline string values

Describe the bug

I'm attempting to embed a 50+ line INI file in a ConfigMap as a string. Whenever I save the file that section loses all of its formatting and it gets squashed into a single line sprinkled with literal \n and "magic line" comment blocks. This makes the embedded INI file unreadable for editing the configuration values so I have to go in and manually find-replace the formatting back how it was and re-indent the block.

Expected Behavior

Format-on-save should not mangle multiline strings. Newlines exist for a reason.

Current Behavior

Format-on-save mangles my strings.

Steps to Reproduce

1. Create the following YAML file in VSCode:

apiVersion: v1
kind: ConfigMap
metadata:
  name: foo
  namespace: bar
data:
  baz.ini: |+
    "[section1]
    a = b
    x = y
    [section2]
    foo=bar"

2. Save the file.

Environment

• Windows
• Mac
• Linux
• other (please specify)

Reproduce the issue in VS Code using the YAML ConfigMap example and format-on-save. Start by tracing the YAML formatter entry point responsible for multiline scalar strings; done means saving the file preserves the multiline value and does not insert literal \n text or comment blocks.