minor symfony#28708 clarify the cache.pools.provider option (dbu)

This PR was merged into the 4.2-dev branch.

Discussion
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clarify the cache.pools.provider option

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | -
| Fixed tickets | -
| License       | MIT
| Doc PR        | symfony/symfony-docs#10390

improve the documentation in Configuration.php with things we found out in symfony/symfony-docs#10390

Commits
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ad4aaf1 clarify the cache.pools.provider option

Author: fabpot

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php

@@ -879,7 +879,7 @@ private function addCacheSection(ArrayNodeDefinition $rootNode)
                                     ->booleanNode('public')->defaultFalse()->end()
                                     ->integerNode('default_lifetime')->end()
                                     ->scalarNode('provider')
-                                        ->info('The service name to use as provider when the specified adapter needs one.')
+                                        ->info('Overwrite the setting from the default provider for this adapter.')
                                     ->end()
                                     ->scalarNode('clearer')->end()
                                 ->end()