New shortline options

[Unoqwy]

• Add short_line_buftypes acting like short_line_list but reading vim.bo.buftype. (closes #156)
• Add inactive_window_shortline. When toggled off, inactive windows keep their regular statusline.

[emmanueltouzery]

as a complete bystander, i'd appreciate the inactive_window_shortline boolean, to differentiate between inactive or short_line buffers. However in an ideal world, it would be nice to be able to differentiate between active & inactive windows, which this boolean doesn't allow. For instance, one might want to be able to have a dimmed or reduced display for inactive windows.

One option instead of an inactive_window_shortline would be a new variable to define inactive_window line display... if it's not defined, inactive windows display the same as short_line windows, same as today. If it is defined however, then you can have inactive windows behaving differently.

That way one could have up to three behaviors: active, inactive, and short list.

[emmanueltouzery]

otherwise I started using this patch for my setup and it seems to work as expected with inactive_window_shortline=false 👍