minor #40180 Fix: Article (localheinz)

This PR was merged into the 4.4 branch.

Discussion
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Fix: Article

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | n/a
| License       | MIT
| Doc PR        | n/a

This pull request

* [x] fixes usages of the indefinite article `a` where `an` should be used instead

Commits
-------

34b320ba97 Fix: Article

Author: xabbuh

DependencyInjection/Configuration.php

@@ -1431,7 +1431,7 @@ private function addHttpClientSection(ArrayNodeDefinition $rootNode)
                                     ->info('A network interface name, IP address, a host name or a UNIX socket to bind to.')
                                 ->end()
                                 ->booleanNode('verify_peer')
-                                    ->info('Indicates if the peer should be verified in a SSL/TLS context.')
+                                    ->info('Indicates if the peer should be verified in an SSL/TLS context.')
                                 ->end()
                                 ->booleanNode('verify_host')
                                     ->info('Indicates if the host should exist as a certificate common name.')
@@ -1570,7 +1570,7 @@ private function addHttpClientSection(ArrayNodeDefinition $rootNode)
                                         ->info('A network interface name, IP address, a host name or a UNIX socket to bind to.')
                                     ->end()
                                     ->booleanNode('verify_peer')
-                                        ->info('Indicates if the peer should be verified in a SSL/TLS context.')
+                                        ->info('Indicates if the peer should be verified in an SSL/TLS context.')
                                     ->end()
                                     ->booleanNode('verify_host')
                                         ->info('Indicates if the host should exist as a certificate common name.')