doc: rephrase dynamic import() description

The description is updated to clarify that dynamic import() is
asynchronous, dynamic, and works in both CJS and ESM contexts.
The new phrasing also avoids implying it is the only method for
loading ES modules in CommonJS.

Fixes: #59077
PR-URL: #59224
Reviewed-By: Antoine du Hamel <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>

Author: meteorqz6

doc/api/esm.md

@@ -331,8 +331,9 @@ fs.readFileSync === readFileSync;
 
 ## `import()` expressions
 
-[Dynamic `import()`][] is supported in both CommonJS and ES modules. In CommonJS
-modules it can be used to load ES modules.
+[Dynamic `import()`][] provides an asynchronous way to import modules. It is
+supported in both CommonJS and ES modules, and can be used to load both CommonJS
+and ES modules.
 
 ## `import.meta`