Minor formatting update in 1992/marangon

1992/marangon/README.md

@@ -24,7 +24,7 @@ NOTE: Some systems need to compile with `-ltermcap` as well as `-lcurses`.
 
 NOTE: The original winning source [marangon.orig.c](marangon.orig.c), found in
 the archive directory, assumed that `exit(3)` returns a value which cause
-problems for some systems where `exit(3)` returns a void.  The file
+problems for some systems where `exit(3)` returns a `void`.  The file
 [marangon.c](marangon.c) avoids this problem.