Include and use WYSIWYG Linebreaks module
From Wysywyg Linebreaks module's page:
The 'force' option is useful for sites where you would like to edit content both with and without wysiwyg editors (so you don't have to manually enter paragraph and linebreak tags everywhere).
Basically, you can edit content that was originally created without a wysiwyg editor (for instance, simply using Drupal's Filtered HTML format, a user may hit enter twice to create a new paragraph—no
tag wraps the block of text in this case), without having to deal with the headache of reformatting everything inside the wysiwyg editor.
User stories
As a site owner i can migrate content created in 'classic Drupal' without needing special conversion and without my WYSIWYG editor subsequently swallowing all my paragraph breaks.
As a content editor i want the flexibility to conveniently write and edit source HTML, including by switching input formats.
(This makes supportnig switching to Markdown more natural for existing content also.)
Proposed solution
https://www.drupal.org/project/wysiwyg_linebreaks
Configure all CKEditor formats to "Force linebreaks" (meaning linebreaks are done with two carriage returns rather than <p></p>
tags.
Remaining work
-
Decide -
Reconfigure
Note that Drupal's linebreak insertion is smart enough not to add extra linebreaks where p tags are already present, so this won't break the formatting of any content that was entered before this change.