message: Clarify cmake-variants.json is not created if one is not present
  The presented variants configuration is just used as default
  if the file does not exist.
  Related to discussion in
diff: @@ -12,7 +12,7 @@ in this manner.
  The most important part of the system is ``cmake-variants.json``, which encodes
  available build settings in such a way that they can be parsed and analyzed by
  automated tooling, as well as human users. Here is the default variants
  -created by CMake Tools when one is not present in a project directory:
  +configuration used by CMake Tools when one is not present in a project directory:
  ~~~json
  {
  