message: Update instructions for code coverage
diff: @@ -171,7 +171,8 @@ following example:
  ### Measuring test coverage:
  -You can measure how much of the code is tested by executing:
  +You can measure how much of the code is tested by adding the `-D REALM_COVERAGE=ON` option to the cmake call that generates the project.
  +This will allow to produce coverage information which is then digestable by gcovr or lcov:
  cd test
  ./realm-tests
  