Formatter: Newlines collapsed inside `javascript_tag` block

[kudoas]

Input:

<%= javascript_tag do %>
  const a = 1
  console.log(a)
<% end %>

Output:

<%= javascript_tag do %>
  const a = 1 console.log(a)
<% end %>

Expected:

<%= javascript_tag do %>
  const a = 1
  console.log(a)
<% end %>

Playground:

https://herb-tools.dev/playground/#DwUgvABAVghgbjAzgYwE4EsAOAXA+tmAcwgBMB7CEAPgCgIJkyA7RbCGCSARgecTIA2AUwB0AsoQAUMAJQ1QEIUxKUqQA

Additional context:

The formatter collapses newlines inside a javascript_tag do block, merging separate JavaScript statements onto a single line. This changes the semantics of the JavaScript code and can cause syntax errors depending on the statements involved.

[laquereric]

javascript/packages/formatter/test/document-formatting.test.ts

+  test("preserves newlines between JavaScript statements inside javascript_tag do block (#1702)", () => {
+    const source = dedent`
+      <%= javascript_tag do %>
+        const a = 1
+        console.log(a)
+      <% end %>
+    `
+    const result = formatter.format(source)
+    expect(result).toEqual(dedent`
+      <%= javascript_tag do %>
+        const a = 1
+        console.log(a)
+      <% end %>
+    `)
+  })