change Alternative code to Alternate code in winner README.md

1986/wall/README.md

@@ -17,7 +17,7 @@ make all
 ./wall
 ```
 
-### Alternative code:
+### Alternate code:
 
 If you have an old compiler or a compiler that supports `-traditional-cpp` you
 might enjoy looking at the original source in [wall.alt.c](wall.alt.c).