FWE patch one (#7131)

Small updates to resolve content issues.

Fixes <Replace with issue link>

#7125 
#7126 
#7118 

---

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  <summary>Contribution guidelines:</summary><br>

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Author: ericwindmill

src/content/learn/tutorial/cli-polish.md

@@ -201,7 +201,7 @@ Finally, update your main application to use the new `onOutput` feature.
     const version = '0.0.1';
 
     void main(List<String> arguments) {
-      var commandRunner = CommandRunner<String>(
+      var commandRunner = CommandRunner(
         onOutput: (String output) async {
           await write(output);
         },

src/content/learn/tutorial/error-handling.md

@@ -67,6 +67,11 @@ represent errors related to command-line arguments.
         super.source,
         super.offset,
       ]);
+
+      @override
+      String toString() {
+        return 'ArgumentException: $message';
+      }
     }
     ```
 

src/content/learn/tutorial/logging.md

@@ -202,7 +202,7 @@ create a logger instance and log messages to a file.
     void main(List<String> arguments) async {
       final errorLogger = initFileLogger('errors');
       final app =
-          CommandRunner<String>(
+          CommandRunner(
               onOutput: (String output) async {
                 await write(output);
               },