minor #12944 Update example to use tagged_locator helper function (HypeMC)

This PR was merged into the 4.3 branch.

Discussion
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Update example to use tagged_locator helper function

For some reason all php examples use the `tagged_locator` helper function except one. This has been changed since I don't see any apparent reason why not to use to & it also keeps the examples more consistent.

Commits
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8b26d01 Update example to use tagged_locator helper function

Author: OskarStark

service_container/service_subscribers_locators.rst

@@ -555,7 +555,7 @@ attribute to the locator service defining the name of this custom method:
         return function(ContainerConfigurator $configurator) {
             $configurator->services()
                 ->set(App\HandlerCollection::class)
-                    ->args([service_locator(tagged('app.handler', null, 'myOwnMethodName'))])
+                    ->args([tagged_locator('app.handler', null, 'myOwnMethodName')])
             ;
         };