Using yaml folded style. The indention in each line will be ignored. A line break will be inserted at the end.
Key: >
This is a very long sentence
that spans several lines in the YAML
but which will be rendered as a string
with only a single carriage return appended to the end.
You can use the "block chomping indicator" to eliminate the trailing line break, as follows:
Key: >-
This is a very long sentence
that spans several lines in the YAML
but which will be rendered as a string
with NO carriage returns.
In either case, each line break is replaced by a space.
There are other control tools available as well (for controlling indentation for example).
