FindHTMLHelp: Use PATH_SUFFIXES to search under Program Files

The find commands already know how to search in variants of the
Program Files folders on Windows.  Use PATH_SUFFIXES to tell them
under what directory within Program Files to find htmlhelp.

Fixes: #16950

Modules/FindHTMLHelp.cmake

@@ -18,28 +18,28 @@
 if(WIN32)
 
   find_program(HTML_HELP_COMPILER
-    hhc
-    "[HKEY_CURRENT_USER\\Software\\Microsoft\\HTML Help Workshop;InstallDir]"
-    "$ENV{ProgramFiles}/HTML Help Workshop"
-    "C:/Program Files/HTML Help Workshop"
+    NAMES hhc
+    PATHS
+      "[HKEY_CURRENT_USER\\Software\\Microsoft\\HTML Help Workshop;InstallDir]"
+    PATH_SUFFIXES "HTML Help Workshop"
     )
 
   get_filename_component(HTML_HELP_COMPILER_PATH "${HTML_HELP_COMPILER}" PATH)
 
   find_path(HTML_HELP_INCLUDE_PATH
-    htmlhelp.h
-    "${HTML_HELP_COMPILER_PATH}/include"
-    "[HKEY_CURRENT_USER\\Software\\Microsoft\\HTML Help Workshop;InstallDir]/include"
-    "$ENV{ProgramFiles}/HTML Help Workshop/include"
-    "C:/Program Files/HTML Help Workshop/include"
+    NAMES htmlhelp.h
+    PATHS
+      "${HTML_HELP_COMPILER_PATH}/include"
+      "[HKEY_CURRENT_USER\\Software\\Microsoft\\HTML Help Workshop;InstallDir]/include"
+    PATH_SUFFIXES "HTML Help Workshop/include"
     )
 
   find_library(HTML_HELP_LIBRARY
-    htmlhelp
-    "${HTML_HELP_COMPILER_PATH}/lib"
-    "[HKEY_CURRENT_USER\\Software\\Microsoft\\HTML Help Workshop;InstallDir]/lib"
-    "$ENV{ProgramFiles}/HTML Help Workshop/lib"
-    "C:/Program Files/HTML Help Workshop/lib"
+    NAMES htmlhelp
+    PATHS
+      "${HTML_HELP_COMPILER_PATH}/lib"
+      "[HKEY_CURRENT_USER\\Software\\Microsoft\\HTML Help Workshop;InstallDir]/lib"
+    PATH_SUFFIXES "HTML Help Workshop/lib"
     )
 
   mark_as_advanced(