[XRay][docs] Update documentation on new default for xray_naive_log=

We've recently changed the default for `xray_naive_log=` to be `false`
instead of `true` to make it more consistent with the FDR mode logging
implementation. This means we will now ask users to explicitly choose
which version of the XRay logging is being used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319400 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed