Template Parts: Limit slug to Latin chars

packages/block-library/src/template-part/edit/placeholder/index.js

@@ -59,13 +59,19 @@ export default function TemplatePartPlaceholder( {
 			startingBlocks = [],
 			title = __( 'Untitled Template Part' )
 		) => {
+			// Currently template parts only allow latin chars.
+			// Fallback slug will receive suffix by default.
+			const cleanSlug =
+				kebabCase( title ).replace( /[^\w-]+/g, '' ) ||
+				'wp-custom-part';
+
 			// If we have `area` set from block attributes, means an exposed
 			// block variation was inserted. So add this prop to the template
 			// part entity on creation. Afterwards remove `area` value from
 			// block attributes.
 			const record = {
 				title,
-				slug: kebabCase( title ),
+				slug: cleanSlug,
 				content: serialize( startingBlocks ),
 				// `area` is filterable on the server and defaults to `UNCATEGORIZED`
 				// if provided value is not allowed.