Docs: Link to jQuery Browser Support page in README.md

Also, remove info about poor console support in IE 9; this version of Migrate
doesn't support it anyway.

README.md

@@ -18,7 +18,7 @@ The following table indicates which jQuery Migrate versions can be used with whi
 | 3.x            | 3.x                    |
 | 4.x            | 4.x                    |
 
-Each jQuery Migrate version supports the same browsers that the jQuery version used with it.
+Each jQuery Migrate version supports the same browsers that the jQuery version used with it. See the [jQuery Browser Support page](https://jquery.com/browser-support/) for more information.
 
 ## Usage
 
@@ -48,7 +48,7 @@ The production build is minified and does not generate console warnings. It will
 
 ## Debugging
 
-The development version of the plugin displays warnings in the browser console. Older browsers such as IE9 doesn't support the console interface. No messages will be generated unless you include a debugging library such as [Firebug Lite](https://getfirebug.com/firebuglite) before including the jQuery Migrate plugin. Developers can also inspect the `jQuery.migrateMessages` array to see what error messages have been generated.
+The development version of the plugin displays warnings in the browser console. Developers can also inspect the `jQuery.migrateMessages` array to see what error messages have been generated.
 
 All warnings generated by this plugin start with the string "JQMIGRATE". A list of the warnings you may see are in [warnings.md](https://github.com/jquery/jquery-migrate/blob/main/warnings.md).