child_process: add env contents types in JSDoc

Use JSDoc to indicate that the `env` object keys and values must be
strings.

Refs: #42489 (comment)

PR-URL: #42494
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

lib/child_process.js

@@ -96,7 +96,7 @@ const MAX_BUFFER = 1024 * 1024;
  * @param {{
  *   cwd?: string;
  *   detached?: boolean;
- *   env?: object;
+ *   env?: Record<string, string>;
  *   execPath?: string;
  *   execArgv?: string[];
  *   gid?: number;
@@ -202,7 +202,7 @@ function normalizeExecArgs(command, options, callback) {
  * @param {string} command
  * @param {{
  *   cmd?: string;
- *   env?: object;
+ *   env?: Record<string, string>;
  *   encoding?: string;
  *   shell?: string;
  *   signal?: AbortSignal;
@@ -256,7 +256,7 @@ ObjectDefineProperty(exec, promisify.custom, {
  * @param {string[]} [args]
  * @param {{
  *   cwd?: string;
- *   env?: object;
+ *   env?: Record<string, string>;
  *   encoding?: string;
  *   timeout?: number;
  *   maxBuffer?: number;
@@ -673,7 +673,7 @@ function abortChildProcess(child, killSignal) {
  * @param {string[]} [args]
  * @param {{
  *   cwd?: string;
- *   env?: object;
+ *   env?: Record<string, string>;
  *   argv0?: string;
  *   stdio?: Array | string;
  *   detached?: boolean;
@@ -746,7 +746,7 @@ function spawn(file, args, options) {
  *   input?: string | Buffer | TypedArray | DataView;
  *   argv0?: string;
  *   stdio?: string | Array;
- *   env?: object;
+ *   env?: Record<string, string>;
  *   uid?: number;
  *   gid?: number;
  *   timeout?: number;
@@ -838,7 +838,7 @@ function checkExecSyncError(ret, args, cmd) {
  *   cwd?: string;
  *   input?: string | Buffer | TypedArray | DataView;
  *   stdio?: string | Array;
- *   env?: object;
+ *   env?: Record<string, string>;
  *   uid?: number;
  *   gid?: number;
  *   timeout?: number;
@@ -875,7 +875,7 @@ function execFileSync(command, args, options) {
  *   cwd?: string;
  *   input?: string | Buffer | TypedArray | DataView;
  *   stdio?: string | Array;
- *   env?: object;
+ *   env?: Record<string, string>;
  *   shell?: string;
  *   uid?: number;
  *   gid?: number;