Add annotation for an empty line

**Describe the problem/challenge you have**
If you have a large template (for example docker swarm stack), the resulting file may be even larger. In addition, it is difficult to navigate in such resulting files due to the absence of empty lines between blocks.

**Describe the solution you'd like**
It would be cool if there was an annotation with which you could put an empty line in the resulting file.
Something like #@ yaml/empty-line

**Anything else you would like to add:**
Nothing)

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