Fix keyboard shortcut for document symbols in Rails add-on docs (#3885)

Add Mac keyboard shortcut to document symbols documentation

Updated the keyboard shortcut documentation to include both Mac (Cmd + Shift + O)
and Windows/Linux (Ctrl + Shift + O) shortcuts, with Mac listed first.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Andy Waite <[email protected]>
Co-authored-by: Claude Sonnet 4.5 <[email protected]>

Author: andyw8

jekyll/rails-add-on.markdown

@@ -62,7 +62,7 @@ document and to allow for quick navigation.
 Ruby LSP already provides document symbols for Ruby files, such as classes, modules, methods, etc. But the Rails add-on
 provides additional document symbols for Rails specific features.
 
-In VS Code, you can open the document symbols view by pressing `Ctrl + Shift + O`.
+In VS Code, you can open the document symbols view by pressing `Cmd + Shift + O` (Mac) or `Ctrl + Shift + O` (Windows/Linux).
 
 ### Active Record Callbacks, Validations, and Associations