message: Add -Zmiri-disable-weak-memory-emulation to README
diff: @@ -317,11 +317,13 @@ to Miri failing to detect cases of undefined behavior in a program.
  can focus on other failures, but it means Miri can miss bugs in your program.
  Using this flag is **unsound**.
  * `-Zmiri-disable-data-race-detector` disables checking for data races. Using
  - this flag is **unsound**.
  + this flag is **unsound**. This implies `-Zmiri-disable-weak-memory-emulation`.
  * `-Zmiri-disable-stacked-borrows` disables checking the experimental
  [Stacked Borrows] aliasing rules. This can make Miri run faster, but it also
  means no aliasing violations will be detected. Using this flag is **unsound**
  (but the affected soundness rules are experimental).
  +* `-Zmiri-disable-weak-memory-emulation` disables the emulation of some C++11 weak
  + memory effects.
  * `-Zmiri-disable-validation` disables enforcing validity invariants, which are
  enforced by default. This is mostly useful to focus on other failures (such
  as out-of-bounds accesses) first. Setting this flag means Miri can miss bugs
  