feat(highlight): add StatusLineTerm and StatusLineTermNC groups

These highlight groups are used for the statusline in :terminal windows.
By default they link to StatusLine and StatusLineNC (respectively), so
there is no visual difference unless a colorscheme defines these groups
separately.

test/functional/ui/cursor_spec.lua

@@ -250,7 +250,7 @@ describe('ui/cursor', function()
         m.attr = { background = Screen.colors.DarkGray }
       end
       if m.id_lm then
-        m.id_lm = 69
+        m.id_lm = 71
       end
     end