CC59892: Removing "public" from code (#5955)

Hello, @mairaw,
This proposed file change comes from dotnet/docs.ru-ru#110.
Contributor comment: "You can not use access modifiers with explicit implementation"

Could you review this contribution and help to merge if agreed?
Many thanks in advance.

Author: v-maudel

docs/csharp/programming-guide/indexers/indexers-in-interfaces.md

@@ -29,23 +29,23 @@ Indexers can be declared on an [interface](../../../csharp/language-reference/ke
  In the preceding example, you could use the explicit interface member implementation by using the fully qualified name of the interface member. For example:  
 
 ```  
-public string ISomeInterface.this[int index]   
+string ISomeInterface.this[int index]   
 {   
 }   
 ```  
 
  However, the fully qualified name is only needed to avoid ambiguity when the class is implementing more than one interface with the same indexer signature. For example, if an `Employee` class is implementing two interfaces, `ICitizen` and `IEmployee`, and both interfaces have the same indexer signature, the explicit interface member implementation is necessary. That is, the following indexer declaration:  
 
 ```  
-public string IEmployee.this[int index]   
+string IEmployee.this[int index]   
 {   
 }   
 ```  
 
  implements the indexer on the `IEmployee` interface, while the following declaration:  
 
 ```  
-public string ICitizen.this[int index]
+string ICitizen.this[int index]
 {   
 }   
 ```