Use ManualPageID as a stand-in alias for wxString

Useful for eliminating many direct mentions of wxString. We added this patch
from Audacity because it coincides with our goal of becoming more platform
agnostic.

Original commits:
- cfbdd2d22e
- 132f04d272

Signed-off-by: Panagiotis Vasilopoulos <hello@alwayslivid.com>

src/widgets/ErrorDialog.cpp

@@ -51,7 +51,7 @@ ErrorDialog::ErrorDialog(
    const TranslatableString & dlogTitle,
    const TranslatableString & message,
    const ManualPageID & helpPage,
-   const std::wstring & log,
+   const wxString & log,
    const bool Close, const bool modal)
 :  wxDialogWrapper(parent, wxID_ANY, dlogTitle,
                    wxDefaultPosition, wxDefaultSize,

src/widgets/ErrorDialog.h

@@ -30,7 +30,7 @@ public:
       const TranslatableString & dlogTitle,
       const TranslatableString & message,
       const ManualPageID & helpPage,
-      const std::wstring & log,
+      const wxString & log,
       const bool Close = true, const bool modal = true);
 
    virtual ~ErrorDialog(){}