Notes for including SSL dependencies (#21262)

* Notes for including SSL dependencies

* lint for ssl

* clarify based on suggestions

Co-authored-by: Andy Gee <[email protected]>

Author: plooploops

docs/core/deploying/trim-self-contained.md

@@ -32,6 +32,39 @@ When the code is indirectly referencing an assembly through reflection, you can
 </ItemGroup>
 ```
 
+### Support for SSL certificates
+
+If your app loads SSL certificates, such as in an ASP.NET Core app, you'll want to ensure that when trimming you prevent trimming assemblies that will help with loading SSL certificates.
+
+We can update our project file to include the following for ASP.NET Core 3.1:
+
+```xml
+<Project Sdk="Microsoft.NET.Sdk.Web">
+  <PropertyGroup>...</PropertyGroup>
+  <!--Include the following for .aspnetcore 3.1-->
+  <ItemGroup>
+    <TrimmerRootAssembly Include="System.Net" />
+    <TrimmerRootAssembly Include="System.Net.Security" />
+    <TrimmerRootAssembly Include="System.Security" />
+  </ItemGroup>
+  ...
+</Project>
+```
+
+If we're using .Net 5.0, we can update our project file to include the following:
+
+```xml
+<Project Sdk="Microsoft.NET.Sdk.Web">
+ <PropertyGroup>...</PropertyGroup>
+ <!--Include the following for .net 5.0-->
+ <ItemGroup>
+    <TrimmerRootAssembly Include="System.Net.Security" />
+    <TrimmerRootAssembly Include="System.Security" />
+  </ItemGroup>
+  ...
+</Project>
+```
+
 ## Trim your app - CLI
 
 Trim your application using the [dotnet publish](../tools/dotnet-publish.md) command. When you publish your app, set the following properties: