Add compiler performance section to table of contents.

(cherry picked from commit a27a7a57bc776dfa6371bcdad5e62cad2a582512)

Author: mbrandonw

Sources/ComposableArchitecture/Documentation.docc/Articles/Performance.md

@@ -9,6 +9,7 @@ becoming slow to execute, SwiftUI view bodies executing more often than expected
 * [View stores](#View-stores)
 * [CPU-intensive calculations](#CPU-intensive-calculations)
 * [High-frequency actions](#High-frequency-actions)
+* [Compiler performance](#Compiler-performance)
 <!--* [Memory usage](#Memory-usage)-->
 
 ### View stores
@@ -305,8 +306,6 @@ case .startButtonTapped:
 This greatly reduces the bandwidth of actions being sent into the system so that you are not 
 incurring unnecessary costs for sending actions.
 
-<!--### Memory usage-->
-
 ### Compiler performance
 
 In very large SwiftUI applications you may experience degraded compiler performance causing long