Update default/extra extension list in docs
Update default/extra extension list in docs

Live4Code/brackets,goldcase/brackets,sgupta7857/brackets,No9/brackets,simon66/brackets,flukeout/brackets,mozilla/brackets,Th30/brackets,SidBala/brackets,Rajat-dhyani/brackets,JordanTheriault/brackets,Rajat-dhyani/brackets,simon66/brackets,sgupta7857/brackets,ScalaInc/brackets,sedge/nimble,No9/brackets,simon66/brackets,Th30/brackets,Th30/brackets,No9/brackets,ashleygwilliams/brackets,nucliweb/brackets,sedge/nimble,sgupta7857/brackets,raygervais/brackets,humphd/brackets,flukeout/brackets,sedge/nimble,Th30/brackets,humphd/brackets,ashleygwilliams/brackets,goldcase/brackets,Rajat-dhyani/brackets,raygervais/brackets,mozilla/brackets,dangkhue27/brackets,SidBala/brackets,ScalaInc/brackets,ScalaInc/brackets,dangkhue27/brackets,JordanTheriault/brackets,dangkhue27/brackets,humphd/brackets,No9/brackets,JordanTheriault/brackets,simon66/brackets,nucliweb/brackets,dangkhue27/brackets,ashleygwilliams/brackets,humphd/brackets,nucliweb/brackets,goldcase/brackets,simon66/brackets,sgupta7857/brackets,mozilla/brackets,SidBala/brackets,Live4Code/brackets,sedge/nimble,flukeout/brackets,mozilla/brackets,flukeout/brackets,raygervais/brackets,goldcase/brackets,sedge/nimble,ScalaInc/brackets,JordanTheriault/brackets,ashleygwilliams/brackets,Live4Code/brackets,sgupta7857/brackets,raygervais/brackets,flukeout/brackets,nucliweb/brackets,mozilla/brackets,SidBala/brackets,humphd/brackets,Rajat-dhyani/brackets,dangkhue27/brackets,Rajat-dhyani/brackets,ashleygwilliams/brackets,Th30/brackets,No9/brackets,JordanTheriault/brackets,nucliweb/brackets,raygervais/brackets,ScalaInc/brackets,goldcase/brackets,SidBala/brackets,Live4Code/brackets,Live4Code/brackets