message: Update the wording of a comment in the LangRef now that multi-threading is no longer an anticipated feature.
diff: @@ -1957,9 +1957,9 @@ Examples:
  ```
  -MLIR does not allow direct references to functions in SSA operands because we
  -anticipate the desire to multithread the compiler, and disallowing SSA values to
  -directly reference a function simplifies this
  +MLIR does not allow direct references to functions in SSA operands because the
  +compiler is multithreaded, and disallowing SSA values to directly reference a
  +function simplifies this
  ([rationale](Rationale.md#multithreading-the-compiler)).
  #### 'divis' operation
  