From<Vec<char>>
From<&'a [char]>
String
Though there are ways to convert a slice or vec of chars into a string, it would be nice to be able to just do `String::from(['a', 'b', 'c'])`, so this PR implements `From<Vec<char>>` and `From<&'a [char]>` for String.
box
vec!
slice::split
Vec::set_len