Name of unusedVars warning type in CMakePresets.json could be misleading

CMake 3.19 removed the --warn-unused-vars command line option, but --warn-unused-cli remains supported. The naming of the unusedVars field under the configurePresets --> warnings section could easily be mistaken as referring to the former instead of the latter (that's exactly what happened to me upon first seeing it).

I suggest that perhaps this presets option should be renamed to unusedCli or something similar to make it match its associated command line option more closely.