Merge pull request #2297 from Jericho/SA1642_struct

SA1642 - Provide a sample constructor documentation for a struct

Author: vweijsters

documentation/SA1642.md

@@ -1,4 +1,4 @@
-## SA1642
+## SA1642
 
 <table>
 <tr>
@@ -41,6 +41,17 @@ public Customer()
 }
 ```
 
+If documenting a struct, the summary must contain the word 'struct' instead of 'class'. For example, the following shows the constructor for the `MyStruct` struct.
+
+```csharp
+/// <summary>
+/// Initializes a new instance of the <see cref="MyStruct"/> struct.
+/// </summary>
+public MyStruct()
+{
+}
+```
+
 If the class contains generic parameters, these can be annotated within the `cref` link using either of the following
 two formats: