Related Gutenberg issue: https://github.com/WordPress/gutenberg/pull/28274
With this change it is going to be possible to use the same pattern that wp_style_add_data uses for RTL handling. If the block style file with "-rtl.css" is included in addition to the regular style referenced in "block.json" file then it is going to be automatically registered.
Props swisspidy, aristath.
See #52301.
git-svn-id: https://develop.svn.wordpress.org/trunk@49982 602fd350-edb4-49c9-b593-d223f7449a82