I18N: Remove `<code>` tags in `invalid_rest_prepare_callback` error message in `register_theme_feature()` for consistency with other strings.

Follow-up to [48611].

See #50758.

git-svn-id: https://develop.svn.wordpress.org/trunk@48612 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/theme.php

@@ -3124,8 +3124,8 @@ function register_theme_feature( $feature, $args = array() ) {
 				'invalid_rest_prepare_callback',
 				sprintf(
 					/* translators: %s: prepare_callback */
-					__( 'The %s must be a callable function.' ),
-					'<code>prepare_callback<code>'
+					__( 'The "%s" must be a callable function.' ),
+					'prepare_callback'
 				)
 			);
 		}