made fact from lecture 13 (somewhat) less trivial

inputs/lecture_13.tex

@@ -274,7 +274,8 @@ We have shown, that $\mu_{n_k} \implies \mu$ along a subsequence.
 We still need to show that $\mu_n \implies \mu$.
 \begin{fact}
     Suppose $a_n$ is a bounded sequence in $\R$,
-    such that any subsequence converges to $a \in \R$.
+    such that any subsequence has a subsequence
+    that converges to $a \in \R$.
     Then $a_n \to  a$.
 \end{fact}
 \begin{subproof}