Export formatIdentifier from compiler lib (#1695)

* export printId as formatIdentifier

* rush change

---------

Co-authored-by: Travis Prescott <tjprescott@users.noreply.github.com>

common/changes/@typespec/compiler/main_2023-03-08-03-23.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@typespec/compiler",
+      "comment": "Export formatIdentifier function from the lib",
+      "type": "none"
+    }
+  ],
+  "packageName": "@typespec/compiler"
+}

packages/compiler/core/formatter.ts

@@ -1,5 +1,6 @@
 import prettier from "prettier";
 import * as typespecPrettierPlugin from "../formatter/index.js";
+export { printId as formatIdentifier } from "../formatter/print/printer.js";
 
 export function formatTypeSpec(code: string, prettierConfig?: prettier.Options): string {
   const output = prettier.format(code, {