Phaqui: Merge branch 'issue_5858' of https://github.com/Phaqui/svelte into issue_5858

test/parser/samples/error-empty-classname-binding/error.json

@@ -0,0 +1,10 @@
+{
+    "code": "empty-classbinding-name",
+    "message": "Class binding name cannot be empty",
+    "start": {
+        "line": 1,
+        "column": 10,
+        "character": 10
+    },
+    "pos": 10
+}

test/parser/samples/error-empty-classname-binding/input.svelte

@@ -0,0 +1 @@
+<h1 class:={true}>Hello</h1>