Global styles: inherit all typography styles.

This PR syncs the changes initially added to Gutenberg in WordPress/gutenberg#70676.

See #9268.
See https://core.trac.wordpress.org/ticket/63700.

Fixes #63700.

git-svn-id: https://develop.svn.wordpress.org/trunk@61021 602fd350-edb4-49c9-b593-d223f7449a82

Author: ellatrix

src/wp-includes/theme.json

@@ -383,6 +383,10 @@
 				"typography": {
 					"fontSize": "inherit",
 					"fontFamily": "inherit",
+					"fontStyle": "inherit",
+					"fontWeight": "inherit",
+					"letterSpacing": "inherit",
+					"textTransform": "inherit",
 					"lineHeight": "inherit",
 					"textDecoration": "none"
 				},