export collisions in 'errorlocate' vs 'validatetools'

[markvanderloo]

R CMD check gives

Found the following significant warnings:
  Warning: replacing previous import ‘errorlocate::is_conditional’ by ‘validatetools::is_conditional’ when loading ‘datacleaning’
  Warning: replacing previous import ‘errorlocate::is_categorical’ by ‘validatetools::is_categorical’ when loading ‘datacleaning’
  Warning: replacing previous import ‘errorlocate::is_linear’ by ‘validatetools::is_linear’ when loading ‘datacleaning’