Update doc/api/esm.md

Co-authored-by: Antoine du Hamel <duhamelantoine1995@gmail.com>

Author: Trott

doc/api/esm.md

@@ -181,7 +181,7 @@ added: v12.10.0
 
 * `text/javascript` for ES Modules
 * `application/json` for JSON (requires `--experimental-json-modules` flag)
-* `application/wasm` for Wasm
+* `application/wasm` for Wasm (requires [--experimental-wasm-modules](cli.md#--experimental-wasm-modules) flag).
 
 `data:` URLs only resolve [_Bare specifiers_][Terminology] for builtin modules
 and [_Absolute specifiers_][Terminology]. Resolving