Support STRICT_TYPED_ITEMIDS

PSDK headers support strict typing that distinguishes between the different pidl pointer types:

• ITEMIDLIST_RELATIVE / PIDLIST_RELATIVE
• ITEMID_CHILD / PITEMID_CHILD
• ITEMIDLIST_ABSOLUTE / PIDLIST_ABSOLUTE

Our code base needs to be updated in steps to use these types before we can switch to their strictly-typed versions.

This is marked starter-project because it's easy to fix this in small parts. Here's how:

• Find an instance of ITEMIDLIST in one of the .h/.idl files in sdk/include/psdk, e.g. shobjidl.idl
• Determine which method of which interface you're looking at (e.g. IShellView2::HandleRename)
• Look up the method on MSDN or in Microsoft's headers and determine the proper parameter type
• git grep for instances of this method (if it's named something like Next or Initialize you may need to write a regular expression that only finds the particular method you're looking for; or simply pick a different one) and replace the parameters

Example:

interface IShellView2 : IShellView

{

[...]

    HRESULT HandleRename(

        [in] LPCITEMIDLIST new_pidl

    );

[...]

}

IShellView2::HandleRename at MSDN: https://docs.microsoft.com/gl-es/windows/win32/api/shobjidl_core/nf-shobjidl_core-ishellview2-handlerename
HandleRename grep: https://git.reactos.org/?p=reactos.git&a=search&h=HEAD&st=grep&s=HandleRename
Replacement: LPCITEMIDLIST -> PCUITEMID_CHILD

OR (more advanced):

• git grep for ITEMIDLIST, either globally or limited to a particular module or subtree
• Determine the correct type for the parameter or variable you found, by looking at assignments to it or interpreting it contextually
• Make the replacement, ensuring that users of the variable or callers of the function use matching types. It may make sense to do all the replacements throughout a whole module at the same time