Themes: Remove mention of “FSE” in Core.

“FSE” themes are block themes.

Fixes #53497.

git-svn-id: https://develop.svn.wordpress.org/trunk@51370 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/data/themedir1/block-theme/index.php

@@ -0,0 +1,4 @@
+<?php
+/**
+ * Block theme.
+ */

tests/phpunit/data/themedir1/block-theme/style.css

@@ -1,7 +1,7 @@
 /*
-Theme Name: FSE Theme
+Theme Name: Block Theme
 Theme URI: https://wordpress.org/
 Description: For testing purposes only.
 Version: 1.0.0
-Text Domain: fse
+Text Domain: block-theme
 */

tests/phpunit/data/themedir1/fse/index.php

@@ -1,4 +0,0 @@
-<?php
-/**
- * Dummy theme.
- */