message: Change notation from Fp and Fn
diff: ///```text
  -/// Foreign field multiplication circuit gates for native field $F_p$ and
  -/// foreign field $F_f$, where $F_p$ is the generic type parameter `F` in code below
  +/// Foreign field multiplication circuit gates for native field $F_n$ and
  +/// foreign field $F_f$, where $F_n$ is the generic type parameter `F` in code below
  /// and the foreign field modulus $f$ is store in the constraint system (`cs.foreign_field_modulus`).
  ///
  /// Inputs:
  ///
  /// $a \cdot b = q \cdot f + r$
  ///
  -/// in $F_f$ by using the native field $F_p$.
  +/// in $F_f$ by using the native field $F_n$.
  ///
  /// **Layout**
  ///
  