Add CHARCLASS to the spell ignore

src/uu/ptx/src/ptx.rs

@@ -5,7 +5,7 @@
 //  * For the full copyright and license information, please view the LICENSE
 //  * file that was distributed with this source code.
 
-// spell-checker:ignore (ToDOs) corasick memchr Roff trunc oset iset
+// spell-checker:ignore (ToDOs) corasick memchr Roff trunc oset iset CHARCLASS
 
 use clap::{crate_version, Arg, Command};
 use regex::Regex;