NLS: Move ligatures to their respective blocks

The separate motivations for why some of these ligatures exist in unicode are completely different amongst each other. ẞ/ß/Æ/Œ are used as standalone letters, fi/fl/ffi/ffl are compatibility forms, and IJ is at some degree between the two use cases. Moreover, long S was standing completely by itself for no reason. This commit moves all of these characters into their respective unicode blocks. Nothing is removed or added.