Fix reference to "undefined behavior" in docs

Author: m4salah

content/en-US/learn/overview.smd

@@ -54,7 +54,7 @@ With Zig one can rely on a safety-enabled build mode, and selectively disable sa
 
 []($code.language('=html').buildAsset('features/3-undefined-behavior.zig'))
 
-Zig uses [undefined behavior](https://ziglang.org/documentation/master/#Undefined-Behavior) as a razor sharp tool for both bug prevention and performance enhancement.
+Zig uses [Illegal Behavior](https://ziglang.org/documentation/master/#Illegal-Behavior) as a razor sharp tool for both bug prevention and performance enhancement.
 
 Speaking of performance, Zig is faster than C.