Format <script> content in glimmer templates (#20012)

Co-authored-by: fisker <lionkay@gmail.com>

changelog_unreleased/handlebars/20012.md

@@ -0,0 +1,21 @@
+#### Support embedded `<script>` (#20012 by @kovsu)
+
+<!-- prettier-ignore -->
+```hbs
+{{! Input }}
+<script>
+  const a =    1;
+  console.log( a );
+</script>
+
+{{! Prettier stable }}
+<script>
+  const a = 1; console.log( a );
+</script>
+
+{{! Prettier main }}
+<script>
+  const a = 1;
+  console.log(a);
+</script>
+```