fix(filter): nbt,predicates,gamemode allow =! operator

[litoj]

hi, I just ran into this, it's a very basic fix, but valuable nevertheless.

I also deleted one line because none of it's groups are being used, (looked with vim's * keybind)

[litoj]

I also implemented highlighting for objectives in the scores filter. I thought it would be nice if the parentheses matched the color of the NBT parentheses, so I changed the link there from mcOp to mcNBTBracket. I don't know what's better though, so no problem changing it back.

I also don't understand vimscript, nor the way the highlighting is being done here, so I just added the code, but I shall improve its structure if needed.