Use more clear names for variables in wxHtmlSelection code.

Call the variables and related methods "character position" instead of
"private position" which wasn't very clear.

Closes #13307.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69870 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/html/htmlwin.cpp

@@ -1214,7 +1214,7 @@ void wxHtmlWindow::OnSize(wxSizeEvent& event)
     {
         m_selection->Set(m_selection->GetFromCell(),
                          m_selection->GetToCell());
-        m_selection->ClearPrivPos();
+        m_selection->ClearFromToCharacterPos();
     }
 
     Refresh();
@@ -1415,7 +1415,7 @@ void wxHtmlWindow::OnInternalIdle()
                         m_selection->Set(wxPoint(x,y), selcell,
                                          m_tmpSelFromPos, m_tmpSelFromCell);
                     }
-                    m_selection->ClearPrivPos();
+                    m_selection->ClearFromToCharacterPos();
                     Refresh();
                 }
             }