doc: add a statement in the documentation.

PR-URL: #35585
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Gireesh Punathil <[email protected]>

Author: PoojaDurgad

doc/api/string_decoder.md

@@ -71,6 +71,7 @@ substitution characters appropriate for the character encoding.
 
 If the `buffer` argument is provided, one final call to `stringDecoder.write()`
 is performed before returning the remaining input.
+After `end()` is called, the `stringDecoder` object can be reused for new input.
 
 ### `stringDecoder.write(buffer)`
 <!-- YAML