Add proposal link with additional info on why sealing types improve performance (#42505)

Author: Youssef1313

docs/fundamentals/code-analysis/quality-rules/ca1852.md

@@ -29,7 +29,7 @@ A type that's not accessible outside its assembly and has no subtypes within its
 
 ## Rule description
 
-When a type isn't accessible outside its assembly and has no subtypes within its containing assembly, it can be safely sealed. Sealing types can improve performance.
+When a type isn't accessible outside its assembly and has no subtypes within its containing assembly, it can be safely sealed. Sealing types can improve performance. For more information, see [Analyzer Proposal: Seal internal/private types](https://github.com/dotnet/runtime/issues/49944)].
 
 If you apply <xref:System.Runtime.CompilerServices.InternalsVisibleToAttribute?displayProperty=fullName> to the assembly that's being analyzed, this rule doesn't flag types that aren't marked as `sealed` by default, because a field may be used by a friend assembly. To analyze the assembly anyway, see [Configure code to analyze](#configure-code-to-analyze).