Group the list of currently supported filetypes by categories

[victordomingos]

The list is growing and is starting to need some sort of organisation. Currently, it displays 4 columns and 29 lines, with items being sorted alphabetically first by line, them by column. It would be a little more readable if it was sorted alphabetically by column instead.

But grouping by filetypes would probably be a great help, even if it makes the list a bit longer.