HtmlHelp.h should use hhctrl.ocx not htmlhelp.dll

[elachlan]

We ran into an error in winforms Unable to load DLL "htmlhelp.dll".
dotnet/winforms#10410

This is the PInvoke generated using CsWin32/Win32metadata

[DllImport("htmlhelp.dll", ExactSpelling = true, EntryPoint = "HtmlHelpW")]
static extern winmdroot.Foundation.HWND LocalExternFunction(winmdroot.Foundation.HWND hwndCaller, winmdroot.Foundation.PCWSTR pszFile, uint uCommand, nuint dwData);

This is the code pulled from ILSpy:

[DllImport("htmlhelp.dll", ExactSpelling = true, PreserveSig = false)]
[Unicode]
[Documentation("https://learn.microsoft.com/windows/win32/api/htmlhelp/nf-htmlhelp-htmlhelpw")]
public static extern HWND HtmlHelpW([Optional][In] HWND hwndCaller, [In][Const] PWSTR pszFile, [In][AssociatedEnum("HTML_HELP_COMMAND")] uint uCommand, [In] UIntPtr dwData);

It should probably point to hhctrl.ocx not htmlhelp.dll.

win32metadata/generation/WinSDK/libMappings.rsp

Lines 26654 to 26655 in a5698d9

	HtmlHelpA=htmlhelp.dll
	HtmlHelpW=htmlhelp.dll

Related: #1345

[elachlan]

CC: @Tanya-Solyanik

[riverar]

Thanks, we'll get that patched up.

[Tanya-Solyanik]

@mikebattista @riverar - When are you planning to do a release with these changes? WInforms has to either revert the change that introduced this issue or to pick up the updated metadata.