Update documentation

doc/mp11/algorithm.adoc

@@ -437,6 +437,8 @@ Supports a value list as `L` under {cpp}17.
 
 Inserts the elements `T...` into the list `L` at position `I` (a zero-based index).
 
+Supports a value list as `L` under {cpp}17. In that case, the elements `T::value...` are inserted.
+
 .mp_insert_c with two elements
 [cols="<.^4m,8*^.^1m",width=85%]
 |===