minor #21617 [DependencyInjection] #[AutoconfigureTag] can be used without tag name (HypeMC)

This PR was merged into the 6.4 branch.

Discussion
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[DependencyInjection] `#[AutoconfigureTag]` can be used without tag name

This was never documented, but when the tag name in `#[AutoconfigureTag]` is not specified, the fully qualified class name of the target is automatically used.

Commits
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0709b35 [DependencyInjection] `#[AutoconfigureTag]` can be used without tag name

Author: javiereguiluz

service_container/tags.rst

@@ -131,6 +131,16 @@ base class or interface::
         // ...
     }
 
+When no tag name is specified, the fully qualified class name (FQCN) of the target is used::
+
+    // src/Security/CustomInterface.php
+
+    #[AutoconfigureTag] // equivalent to #[AutoconfigureTag(self::class)]
+    interface CustomInterface
+    {
+        // ...
+    }
+
 .. tip::
 
     If you need more capabilities to autoconfigure instances of your base class