Eeschema: ensure wire / bus auto-start respects bus labels

Fixes #13506 and further ensures correct behaviour for heirarchical labels and sheet pins

eeschema/tools/ee_selection_tool.cpp

@@ -731,6 +731,16 @@ OPT_TOOL_EVENT EE_SELECTION_TOOL::autostartEvent( TOOL_EVENT* aEvent, EE_GRID_HE
             else if( line->IsGraphicLine() )
                 newEvt = EE_ACTIONS::drawLines.MakeEvent();
         }
+        else if( aItem->Type() == SCH_LABEL_T || aItem->Type() == SCH_HIER_LABEL_T
+                 || aItem->Type() == SCH_SHEET_PIN_T )
+        {
+            SCH_LABEL_BASE* label = static_cast<SCH_LABEL_BASE*>( aItem );
+            SCH_CONNECTION  possibleConnection( label->Schematic()->ConnectionGraph() );
+            possibleConnection.ConfigureFromLabel( label->GetText() );
+
+            if( possibleConnection.IsBus() )
+                newEvt = EE_ACTIONS::drawBus.MakeEvent();
+        }
 
         newEvt->SetMousePosition( pos );
         newEvt->SetHasPosition( true );