message: Add trailing $$
  Add trailing $$
diff: @@ -42,7 +42,7 @@ class RMSprop(optimizer_v2.OptimizerV2):
  $$mean_square_t = rho * mean_square{t-1} + (1-rho) * gradient ** 2$$
  $$mom_t = momentum * mom_{t-1} + learning_rate * gradient / \sqrt{ /
  mean_square_t + \epsilon}$$
  - $$variable_t := variable_{t-1} - mom_t
  + $$variable_t := variable_{t-1} - mom_t$$
  This implementation of RMSprop uses plain momentum, not Nesterov momentum.
  @@ -53,7 +53,7 @@ class RMSprop(optimizer_v2.OptimizerV2):
  $$mean_square_t = rho * mean_square_{t-1} + (1-rho) * gradient ** 2$$
  $$mom_t = momentum * mom_{t-1} + learning_rate * gradient /
  sqrt(mean_square_t - mean_grad_t**2 + epsilon)$$
  - $$variable_t := variable_{t-1} - mom_t
  + $$variable_t := variable_{t-1} - mom_t$$
  References
  See ([pdf]
  