bpo-38589: Fixes HTML Help shortcut when Windows is not installed to C drive (GH-16968)

diff --git a/Tools/msi/doc/doc.wxs b/Tools/msi/doc/doc.wxs
index 306fb11..cd1a68c 100644
--- a/Tools/msi/doc/doc.wxs
+++ b/Tools/msi/doc/doc.wxs
@@ -8,7 +8,7 @@
         <PropertyRef Id="REGISTRYKEY" />
         
         <Property Id="HHExe" Value="C:\Windows\hh.exe" />
-        <CustomAction Id="SetHHExe" Property="HHCExe" Value='[WindowsFolder]\hh.exe' Execute="immediate" />
+        <CustomAction Id="SetHHExe" Property="HHExe" Value='[WindowsFolder]\hh.exe' Execute="immediate" />
         <InstallExecuteSequence>
             <Custom Action="SetHHExe" Before="CostFinalize">1</Custom>
         </InstallExecuteSequence>