Align leading comment of union type elements (#18833)

changelog_unreleased/typescript/18833.md

@@ -0,0 +1,42 @@
+#### Align JSDoc before union type elements (#18833 by @fisker)
+
+<!-- prettier-ignore -->
+```tsx
+// Input
+type A =
+  |
+  /**
+   * Comment
+   */
+  a
+  | (b | c);
+type A2 =
+  |
+  // comment
+  a
+  | (b | c);
+
+// Prettier stable
+type A =
+  | /**
+   * Comment
+   */
+  a
+  | (b | c);
+type A2 =
+  | // comment
+  a
+  | (b | c);
+
+// Prettier main
+type A =
+  | /**
+     * Comment
+     */
+    a
+  | (b | c);
+type A2 =
+  | // comment
+    a
+  | (b | c);
+```