doc: improve wording in esm.md

Simplify complex sentence. Remove use of "straightforward".

PR-URL: nodejs#32427
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

doc/api/esm.md

@@ -620,8 +620,8 @@ stateless):
 
 ##### Approach #2: Isolate State
 
-The most straightforward `package.json` would be one that defines the separate
-CommonJS and ES module entry points directly:
+A `package.json` file can define the separate CommonJS and ES module entry
+points directly:
 
 <!-- eslint-skip -->
 ```js