Add obsolete warning message for RSI short hand
Add obsolete warning message for RSI short hand

The default moving average type for RSI should be wilder's avg.
We'll change the default value in about a month or so.

kaffeebrauer/Lean,StefanoRaggi/Lean,kaffeebrauer/Lean,jameschch/Lean,QuantConnect/Lean,kaffeebrauer/Lean,StefanoRaggi/Lean,QuantConnect/Lean,jameschch/Lean,AnshulYADAV007/Lean,Jay-Jay-D/LeanSTP,StefanoRaggi/Lean,AlexCatarino/Lean,AnshulYADAV007/Lean,AlexCatarino/Lean,jameschch/Lean,Jay-Jay-D/LeanSTP,StefanoRaggi/Lean,StefanoRaggi/Lean,AlexCatarino/Lean,QuantConnect/Lean,kaffeebrauer/Lean,AnshulYADAV007/Lean,JKarathiya/Lean,Jay-Jay-D/LeanSTP,jameschch/Lean,kaffeebrauer/Lean,JKarathiya/Lean,AnshulYADAV007/Lean,Jay-Jay-D/LeanSTP,AnshulYADAV007/Lean,Jay-Jay-D/LeanSTP,jameschch/Lean,AlexCatarino/Lean,JKarathiya/Lean,JKarathiya/Lean,QuantConnect/Lean