Try again with math-like externals (#4629)

* Try again with math-like externals

* clippy 1.59

* clippy 1.59

* clippy 1.59

crates/nu-command/src/system/run_external.rs

@@ -397,7 +397,7 @@ impl ExternalCommand {
             // Clean the args before we use them:
             // https://stackoverflow.com/questions/1200235/how-to-pass-a-quoted-pipe-character-to-cmd-exe
             // cmd.exe needs to have a caret to escape a pipe
-            let arg = arg.item.replace("|", "^|");
+            let arg = arg.item.replace('|', "^|");
             process.arg(&arg);
         }
         process