corrected punctuation

labml_nn/rl/ppo/gae.py

@@ -33,7 +33,7 @@ class GAE:
         \hat{A_t^{(\infty)}} &= r_t + \gamma r_{t+1} +\gamma^2 r_{t+1} + ... - V(s)
         \end{align}
 
-        $\hat{A_t^{(1)}}$ is high bias, low variance whilst
+        $\hat{A_t^{(1)}}$ is high bias, low variance, whilst
         $\hat{A_t^{(\infty)}}$ is unbiased, high variance.
 
         We take a weighted average of $\hat{A_t^{(k)}}$ to balance bias and variance.