Merge pull request rails#49014 from akhilgkrishnan/add-missing-dollar

[skip ci] Added missing $ for a bash

Author: byroot

guides/source/3_2_release_notes.md

@@ -151,7 +151,7 @@ Railties
 * Allow scaffold/model/migration generators to accept "index" and "uniq" modifiers. For example,
 
     ```bash
-    bin/rails g scaffold Post title:string:index author:uniq price:decimal{7,2}
+    $ bin/rails g scaffold Post title:string:index author:uniq price:decimal{7,2}
     ```
 
     will create indexes for `title` and `author` with the latter being a unique index. Some types such as decimal accept custom options. In the example, `price` will be a decimal column with precision and scale set to 7 and 2 respectively.