Use explicit extensions for imports within src (#58421)

src/tsserver/common.ts

@@ -1,4 +1,4 @@
-import * as ts from "../typescript/typescript";
+import * as ts from "../typescript/typescript.js";
 
 /** @internal */
 export function getLogLevel(level: string | undefined) {

src/tsserver/nodeServer.ts

@@ -23,13 +23,13 @@ import {
     validateLocaleAndSetLanguage,
     versionMajorMinor,
     WatchOptions,
-} from "../typescript/typescript";
-import * as ts from "../typescript/typescript";
+} from "../typescript/typescript.js";
+import * as ts from "../typescript/typescript.js";
 import {
     getLogLevel,
     StartInput,
     StartSessionOptions,
-} from "./common";
+} from "./common.js";
 
 interface LogOptions {
     file?: string;

src/tsserver/server.ts

@@ -1,6 +1,6 @@
-import * as ts from "../typescript/typescript";
-import { StartInput } from "./common";
-import { initializeNodeSystem } from "./nodeServer";
+import * as ts from "../typescript/typescript.js";
+import { StartInput } from "./common.js";
+import { initializeNodeSystem } from "./nodeServer.js";
 
 function findArgumentStringArray(argName: string): readonly string[] {
     const arg = ts.server.findArgument(argName);