Fix comments around heritage clauses (#19897)

changelog_unreleased/typescript/19897-2.md

@@ -0,0 +1,32 @@
+#### Fix comment before the first heritage clause (#19897 by @fisker)
+
+<!-- prettier-ignore -->
+```tsx
+// Input
+class Foo
+  extends Bar
+  implements
+    // Comment for Ifoo
+    IFoo,
+    IBar {
+  // ...
+}
+
+// Prettier stable
+class Foo
+  extends Bar
+  // Comment for Ifoo
+  implements IFoo, IBar {
+  // ...
+}
+
+// Prettier main
+class Foo
+  extends Bar
+  implements
+    // Comment for Ifoo
+    IFoo,
+    IBar {
+  // ...
+}
+```

changelog_unreleased/typescript/19897.md

@@ -0,0 +1,30 @@
+#### Fix unstable comment before the first heritage clause (#19897 by @fisker)
+
+<!-- prettier-ignore -->
+```tsx
+// Input
+class MyClass extends MySuperClass implements /* foo */ ISomething, /* bar */ IOtherThing, /* baz */ IThirdThing {
+}
+
+// Prettier stable (First format)
+class MyClass
+  extends MySuperClass
+  implements
+    /* foo */ ISomething,
+    /* bar */ IOtherThing,
+    /* baz */ IThirdThing {}
+
+// Prettier stable (Second format)
+class MyClass
+  extends MySuperClass
+  /* foo */
+  implements ISomething, /* bar */ IOtherThing, /* baz */ IThirdThing {}
+
+// Prettier main
+class MyClass
+  extends MySuperClass
+  implements
+    /* foo */ ISomething,
+    /* bar */ IOtherThing,
+    /* baz */ IThirdThing {}
+```