MergeYaml does not process multiline scalar value blocks properly when multiline block is located in a subkey

[jevanlingen]

What's changed?

Improve formatting of multiline scalar values.

What's your motivation?

Since

• fix: MergeYaml block indentation not as expected #4358

multiline scalar value blocks should work now, but it did not work properly when the key of the scalar is located deeper in the tree like:

deep:
  object:
    script: |
       #!/bin/bash
       echo "hello"

Secondly, there was no support for values with different levels of indentation, which is valid in Yaml is as well:

script: |
  #!/bin/bash
         echo "hello"

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've used the IntelliJ IDEA auto-formatter on affected files

[timtebeek]

Great to see this quickly fixed.