Seems about due for the vim completions to be updated again

@pboettch @brad.king A number of new variables and properties have been added to CMake since the last time the vim completions in Auxiliary/vim were updated. Is it time to re-run whatever script is used to update these things?

For reference, these are maintained here:

CMake’s source tree has a Utilities/Scripts/update-vim-syntax.bash script to update from there.