minor #14740 [Console] Update lockable_trait.rst (adubovskoy)

This PR was merged into the 5.2 branch.

Discussion
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[Console] Update lockable_trait.rst

Misprint has been fixed: added ":"

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Commits
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b885099 Update lockable_trait.rst

Author: javiereguiluz

console/lockable_trait.rst

@@ -39,7 +39,7 @@ that adds two convenient methods to lock and release commands::
             // automatically when the execution of the command ends
             $this->release();
 
-            return Command:SUCCESS;
+            return Command::SUCCESS;
         }
     }