Add note about timing of type loader exceptions (dotnet#7468)

Author: jkotas

xml/System.IO/DirectoryNotFoundException.xml

@@ -55,10 +55,6 @@
 ## Remarks  
  `DirectoryNotFoundException` uses the HRESULT COR_E_DIRECTORYNOTFOUND which has the value 0x80070003. Note that `DirectoryNotFoundException` is also thrown when COM interop programs see the HRESULT STG_E_PATHNOTFOUND, which has the value 0x80030003.  
   
- If your code does not have <xref:System.Security.Permissions.FileIOPermissionAttribute.PathDiscovery%2A> permission, the error message for this exception may only contain file or directory names instead of fully qualified paths.  
-  
-   
-  
 ## Examples  
  The following example shows how to force and recover from a <xref:System.IO.DirectoryNotFoundException>.  
   

xml/System.IO/FileLoadException.xml

@@ -50,7 +50,8 @@
   <Docs>
     <summary>The exception that is thrown when a managed assembly is found but cannot be loaded.</summary>
     <remarks>
-      <format type="text/markdown"><![CDATA[  
+      <format type="text/markdown">
+      <![CDATA[  
   
 ## Remarks  
  Represents the error that occurs when a <xref:System.Reflection.Assembly> file is found but cannot be loaded.  
@@ -59,15 +60,15 @@
   
  `FileLoadException` has the default HRESULT of COR_E_FILELOAD, which has the value 0x80131621, but this is not the only possible HRESULT.  
   
- If your code does not have <xref:System.Security.Permissions.FileIOPermissionAttribute.PathDiscovery%2A> permission, the error message for this exception may only contain file or directory names instead of fully qualified paths.  
+The exact timing of when static assembly references are loaded is unspecified. This exception may be thrown before the method that statically references the assembly that failed to load starts executing.
   
 > [!NOTE]
 >  This exception is not included in the [.NET for Windows Store apps](https://go.microsoft.com/fwlink/?LinkID=247912) or the [Portable Class Library](/dotnet/standard/cross-platform/cross-platform-development-with-the-portable-class-library), but it is thrown by some members that are. To catch the exception in that case, write a `catch` statement for <xref:System.IO.IOException> instead.  
   
  **Associated Tips**  
   
- **Make sure that the file is a valid .NET Framework assembly.**  
- This exception is thrown if the file is not a valid .NET Framework assembly. For more information, see <xref:System.Reflection.Assembly>.  
+ **Make sure that the file is a valid .NET assembly.**  
+ This exception is thrown if the file is not a valid .NET assembly. For more information, see <xref:System.Reflection.Assembly>.  
   
  **Check to make sure an assembly or module was not loaded twice with two different evidences.**  
  Evidence is the set of information that constitutes input to security policy decisions, such as what permissions can be granted to code. For more information, see <xref:System.EnterpriseServices.Internal.Publish.GacRemove%2A> and <xref:System.Reflection.Assembly.Evidence%2A>  

xml/System.IO/FileNotFoundException.xml

@@ -66,8 +66,6 @@
 ## Remarks  
  `FileNotFoundException` uses the HRESULT COR_E_FILENOTFOUND which has the value 0x80070002.  
   
- If your code does not have <xref:System.Security.Permissions.FileIOPermissionAttribute.PathDiscovery%2A> permission, the error message for this exception may only contain file or directory names instead of fully qualified paths.  
-  
  ]]></format>
     </remarks>
     <altmember cref="T:System.Exception" />

xml/System.IO/PathTooLongException.xml

@@ -53,8 +53,6 @@
       <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
- If your code does not have <xref:System.Security.Permissions.FileIOPermissionAttribute.PathDiscovery%2A?displayProperty=nameWithType> permission, the error message for this exception may contain only file or directory names instead of full paths.  
-  
  In apps that run under versions of the .NET Framework prior to the .NET Framework 4.6.2, full paths must not exceed 260 characters to maintain compatibility with Windows operating systems. Any path in excess of 260 characters automatically throws a <xref:System.IO.PathTooLongException>. For more information about this restriction, see the entry [Long Paths in .NET](https://go.microsoft.com/fwlink/?LinkID=163666) in the BCL Team blog.  
   
 > [!NOTE]

xml/System/MissingMethodException.xml

@@ -64,7 +64,9 @@
  <xref:System.MissingMethodException> uses the HRESULT COR_E_MISSINGMETHOD, that has the value 0x80131513.  
   
  For a list of initial property values for an instance of <xref:System.MissingMethodException>, see the <xref:System.MissingMethodException.%23ctor%2A> constructors.  
-  
+ 
+The exact timing of when statically referenced methods are loaded is unspecified. This exception may be thrown before the method that references the missing method starts executing.
+ 
 > [!NOTE]
 >  This exception is not included in [.NET for Windows Store apps](https://go.microsoft.com/fwlink/?LinkID=247912) or the [Portable Class Library](/dotnet/standard/cross-platform/cross-platform-development-with-the-portable-class-library), but it is thrown by some members that are. To catch the exception in that case, write a `catch` statement for <xref:System.MissingMemberException> instead.  
   

xml/System/TypeLoadException.xml

@@ -71,6 +71,8 @@
   
  For a list of initial property values for an instance of <xref:System.TypeLoadException>, see the <xref:System.TypeLoadException.%23ctor%2A> constructors.  
   
+The exact timing of when statically referenced types are loaded is unspecified. This exception may be thrown before the method that references the missing type starts executing.
+  
  ]]></format>
     </remarks>
     <altmember cref="T:System.Exception" />