Fixup the testing stuff

Signed-off-by: Marcel Müller <neikos@neikos.email>

tests/cases/2-ast@simple.snap

@@ -0,0 +1,15 @@
+---
+source: tests/file_tests.rs
+expression: ast
+input_file: tests/cases/simple.temple
+---
+TemplateAst {
+    root: [
+        StaticContent(
+            TemplateToken {
+                kind: Content,
+                source: "Hello World!",
+            },
+        ),
+    ],
+}