fix link

jakobkogler · jakobkogler · commit baa21fd60c90 · 2023-01-26T19:08:01.000+01:00
diff --git a/src/combinatorics/inclusion-exclusion.md b/src/combinatorics/inclusion-exclusion.md
@@ -148,7 +148,7 @@ where $0 \le x_i \le 8 ~ (i = 1,2,\ldots 6)$.
 
 Task: count the number of solutions to the equation.
 
-Forget the restriction on $x_i$ for a moment and just count the number of nonnegative solutions to this equation. This is easily done using [Stars and Bars](stars_and_bars.html):
+Forget the restriction on $x_i$ for a moment and just count the number of nonnegative solutions to this equation. This is easily done using [Stars and Bars](stars_and_bars.md):
 we want to break a sequence of $20$ units into $6$ groups, which is the same as arranging $5$ _bars_ and $20$ _stars_:
 
 $$N_0 = \binom{25}{5}$$
