moveToNewFile: Support selecting the name of a declaration (#24331)

tests/cases/fourslash/moveToNewFile_selectionOnName.ts

@@ -0,0 +1,19 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /a.ts
+////export {};
+////function e[|f|]f() { gee(); }
+////function gee() { eff(); }
+
+verify.moveToNewFile({
+    newFileContents: {
+        "/a.ts":
+`import { eff } from "./eff";
+
+export {};
+export function gee() { eff(); }`,
+        "/eff.ts":
+`import { gee } from "./a";
+export function eff() { gee(); }`,
+    },
+});