Snap mouse point before picking startItem.

Fixes https://gitlab.com/kicad/code/kicad/issues/9700

pcbnew/router/pns_tool_base.cpp

@@ -279,7 +279,7 @@ void TOOL_BASE::updateStartItem( const TOOL_EVENT& aEvent, bool aIgnorePads )
     else
         p = cp;
 
-    m_startItem = pickSingleItem( p, -1, -1, aIgnorePads );
+    m_startItem = pickSingleItem( cp, -1, -1, aIgnorePads );
 
     if( !m_gridHelper->GetUseGrid() && m_startItem && !m_startItem->Layers().Overlaps( tl ) )
         m_startItem = nullptr;