Fix comments

Author: VSadov

src/tests/async/Directory.Build.targets

@@ -1,11 +1,11 @@
 <Project>
   <PropertyGroup>
-    <!-- disable building for configurations that do not not yet support runtime async. -->
+    <!-- disable building for configurations that do not yet support runtime async. -->
     <DisableProjectBuild Condition="'$(RuntimeFlavor)' == 'mono' or '$(TestBuildMode)' == 'nativeaot' or '$(TargetArchitecture)' == 'wasm'">true</DisableProjectBuild>
   </PropertyGroup>
 
   <PropertyGroup>
-    <!-- Disable runtime async testing in main repo by default. Uncomment the following to enable. -->
+    <!-- Disable runtime async testing in main repo by default. Remove the following to enable. -->
     <!--<DisableProjectBuild>true</DisableProjectBuild>-->
   </PropertyGroup>