Coerce process.exitCode to number to match local usage (tj#2209)

Author: shadowspawn

lib/command.js

@@ -2392,7 +2392,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
 
   help(contextOptions) {
     this.outputHelp(contextOptions);
-    let exitCode = process.exitCode || 0;
+    let exitCode = Number(process.exitCode ?? 0); // process.exitCode does allow a string of an integer, but we prefer just a number
     if (
       exitCode === 0 &&
       contextOptions &&