Don't use non-ASCII characters in interface headers

Replace "’s" with "'s" in interface headers as the former broke wxPython
build with SIP under MSW.

Closes #22605.

interface/wx/clrpicker.h

@@ -45,7 +45,7 @@ wxEventType wxEVT_COLOURPICKER_DIALOG_CANCELLED;
     @event{EVT_COLOURPICKER_CHANGED(id, func)}
            The user changed the colour selected in the control either using the
            button or using text control (see @c wxCLRP_USE_TEXTCTRL; note that
-           in this case the event is fired only if the user’s input is valid,
+           in this case the event is fired only if the user's input is valid,
            i.e. recognizable). When using a popup dialog for changing the
            colour, this event is sent only when the changes in the dialog are
            accepted by the user, unlike @c EVT_COLOURPICKER_CURRENT_CHANGED.

interface/wx/webview.h

@@ -851,7 +851,7 @@ public:
     virtual bool RemoveScriptMessageHandler(const wxString& name);
 
     /**
-        Injects the specified script into the webpage’s content.
+        Injects the specified script into the webpage's content.
 
         @param javascript The javascript code to add.
         @param injectionTime Specifies when the script will be executed.