bpo-37396, PCbuild: Include "_d" in "Killing any running ..." message (GH-14370)

Add $(PyDebugExt) in "Killing any running python$(PyDebugExt).exe
instances...".

Author: vstinner

PCbuild/pyproject.props

@@ -127,7 +127,7 @@ foreach (System.Diagnostics.Process p in System.Diagnostics.Process.GetProcesses
   </UsingTask>
 
   <Target Name="KillPython" BeforeTargets="PrepareForBuild" Condition="'$(KillPython)' == 'true'">
-    <Message Text="Killing any running python.exe instances..." Importance="high" />
+    <Message Text="Killing any running python$(PyDebugExt).exe instances..." Importance="high" />
     <KillPython FileName="$(OutDir)python$(PyDebugExt).exe" />
   </Target>