Apply 2 suggestion(s) to 1 file(s)

Co-authored-by: Dana Binkley <binkley@adacore.com>

Author: frank-at-adacore

courses/rust_essentials/200_error_handling/07-thiserror.rst

@@ -121,15 +121,15 @@ Why Use "thiserror"?
       #[error("Environment variable {0} not set")]
       ConfigError(String),
 
-      #[error("File system error")] // Automatically wraps io::Error
+      #[error("File system error")] // Automatically wraps 'io::Error'
       IoError(#[from] std::io::Error),
   }
 
   fn main() -> Result<(), MyError> {
       // 1. Manual error creation
       let _ = Err(MyError::ConfigError("PORT".into()))?;
 
-      // 2. Automatic conversion using ? (this returns IoError)
+      // 2. Automatic conversion using '?' (this returns 'IoError')
       let _f = File::open("missing.txt")?;
 
       Ok(())