:title
list_map

:sig
Use map(StringList items, function<String (String)> f)

:see
map
filter
StringList

:content
`list_map()` was removed because `StringList` is `std::vector<String>` and the generic `map()` helper covers the same behavior without a second implementation to maintain.

Use:

```cpp
auto upper = map(names, [](String s) { return(to_upper(s)); });
```
