Before calling "attach" a screen object is just a dummy container for
(row, col) values whose purpose is to be sent as part of the "attach"
function call anyway.
Just create the screen in an attached state directly. Keep the complete
(row, col, options) config together. It is still completely valid to
later detach and re-attach as needed, including to another session.
Problem:
- `vim.highlight` module does not follow `:help dev-name-common`, which
documents the name for "highlight" as "hl".
- Shorter names are usually preferred.
Solution:
Rename `vim.highlight` to `vim.hl`.
This is not a breaking change until 2.0 (or maybe never).
