message: Update docs with possible locations for variants file
diff: @@ -11,6 +11,9 @@ interface for creating and building variants is ``cmake-variants.json``, or
  For smaller or simple projects, providing a custom ``cmake-variants.yaml`` is
  unnecessary, and the default CMake build types will work just fine.
  +The variants file can be placed in the root of the project directory, or in the
  +``.vscode`` subdirectory for the project.
  +
  .. note::
  CMake Tools provides a YAML validation schema, which is only checked in the
  