Add column parameter to wxListCtrl::GetItemText().

Allow retrieving the text from columns other than the first one directly.

Add implementations for MSW and generic versions, documentation and a unit
test.

Closes #11597.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64281 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/listctrl.cpp

@@ -1031,12 +1031,13 @@ bool wxListCtrl::SetItemColumnImage(long item, long column, int image)
 }
 
 // Gets the item text
-wxString wxListCtrl::GetItemText(long item) const
+wxString wxListCtrl::GetItemText(long item, int col) const
 {
     wxListItem info;
 
     info.m_mask = wxLIST_MASK_TEXT;
     info.m_itemId = item;
+    info.m_col = col;
 
     if (!GetItem(info))
         return wxEmptyString;