Add build-only diagnostic note to all relevant CS error documentation

Co-authored-by: BillWagner <493969+BillWagner@users.noreply.github.com>

Author: Copilot

docs/csharp/misc/cs0017.md

@@ -13,6 +13,8 @@ ms.assetid: 5e2a3eb3-6f6e-485d-8293-ceabea4d6905
 Program 'output file name' has more than one entry point defined. Compile with /main to specify the type that contains the entry point.  
 
  A program can only have one [Main](../fundamentals/program-structure/main-command-line.md) method.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
 
  To resolve this error, you can either delete all Main methods in your code, except one, or you can use the [**StartupObject**](../language-reference/compiler-options/advanced.md#mainentrypoint-or-startupobject) compiler option to specify which Main method you want to use.  
 

docs/csharp/misc/cs0028.md

@@ -13,6 +13,8 @@ ms.assetid: 47df919f-01fa-45ae-a4b7-912445e679e2
 'function declaration' has the wrong signature to be an entry point  
 
  The method declaration for `Main` was invalid: it was declared with an invalid signature. `Main` must be declared as static and it must return either [int](../language-reference/builtin-types/integral-numeric-types.md) or [void](../language-reference/builtin-types/void.md). For more information, see [Main() and Command-Line Arguments](../fundamentals/program-structure/main-command-line.md).  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
 
  The following sample generates CS0028:  
 

docs/csharp/misc/cs0067.md

@@ -13,6 +13,8 @@ ms.assetid: df75220b-0b93-45ec-8655-98d9333b0bb7
 The event 'event' is never used  
 
  An [event](../language-reference/keywords/event.md) was declared but never used in the class in which it was declared.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
 
  The following sample generates CS0067:  
 

docs/csharp/misc/cs0169.md

@@ -14,8 +14,7 @@ The private field 'class member' is never used
 
  A private variable was declared but never referenced. A common way to generate this warning is when you declare a private member of a class and do not use it.  
 
-> [!NOTE]
-> This warning is only reported during explicit **Build** or **Rebuild** operations. It does not appear during typing in the IDE as part of IntelliSense diagnostics. This means that if you fix the warning by using the field or removing it, the warning might persist in the error list until you build or rebuild the project again.
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
 
  The following sample generates CS0169:  
 

docs/csharp/misc/cs0279.md

@@ -13,6 +13,8 @@ ms.assetid: 5e5faa8f-3d5b-4999-aa62-ff7f131a3e04
 'type name' does not implement the 'pattern name' pattern. 'method name' is either static or not public.  
 
  There are several statements in C# that rely on defined patterns, such as `foreach` and `using`. For example, `foreach` relies on the collection class implementing the enumerable pattern. This error occurs when the compiler is unable to make the match due to a method being declared `static` or not `public`. Methods in patterns are required to be instances of classes, and to be public.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
 
 ## Example  
 

docs/csharp/misc/cs0402.md

@@ -13,6 +13,8 @@ ms.assetid: 5a252c95-18c7-4569-bae0-e1f7b582cf6a
 'identifier' : an entry point cannot be generic or in a generic type  
 
  The entry point was found in a generic type. To remove this warning, implement Main in a non-generic class or struct.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
 
 ```csharp  
 // CS0402.cs  

docs/csharp/misc/cs0414.md

@@ -12,6 +12,8 @@ ms.assetid: 6a0a80be-799b-4d9c-a7e0-6b91e9ce7be0
 
 The private field 'field' is assigned but its value is never used
 
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
+
 This warning can occur in several scenarios in which the compiler can verify that a variable is never referenced:
 
 - A private field is assigned a constant value but is never subsequently read. The unnecessary assignment could effect performance. Consider removing the field.

docs/csharp/misc/cs0649.md

@@ -13,6 +13,8 @@ ms.assetid: 37137b18-12ed-4a0f-92e6-ee5fb0532ef3
 Field 'field' is never assigned to, and will always have its default value 'value'  
 
  The compiler detected an uninitialized private or internal field declaration that is never assigned a value.  
+
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
 
  The following sample generates CS0649:  
 

docs/csharp/misc/cs5001.md

@@ -14,6 +14,8 @@ Program does not contain a static 'Main' method suitable for an entry point
 
 This error occurs when no static `Main` method with a correct signature is found in the code that produces an executable file. It also occurs if the entry point function, `Main`, is defined with the wrong case, such as lower-case `main`. For information about the rules that apply to the `Main` method, see [Main() and Command-Line Arguments](../fundamentals/program-structure/main-command-line.md).
 
+[!INCLUDE[csharp-build-only-diagnostic-note](~/includes/csharp-build-only-diagnostic-note.md)]
+
 If the `Main` method has an `async` modifier, make sure that the [selected C# language version](../language-reference/configure-language-version.md) is 7.1 or higher and to use `Task` or `Task<int>` as the return type.
 
 The `Main` method is only required when compiling an executable file, that is, when the **exe** or **winexe** element of the [**TargetType**](../language-reference/compiler-options/output.md#targettype) compiler option is specified. The following Visual Studio project types specify one of these options by default:

includes/csharp-build-only-diagnostic-note.md

@@ -0,0 +1,2 @@
+> [!NOTE]
+> This warning is only reported during explicit **Build** or **Rebuild** operations. It does not appear during typing in the IDE as part of IntelliSense diagnostics. This means that if you fix the warning by using the field or removing it, the warning might persist in the error list until you build or rebuild the project again.