Doc: Remove man page reference to congestion.config which no longer exists.
Doc: Remove man page reference to congestion.config which no longer exists.

dyrock/trafficserver,bryancall/trafficserver,chitianhao/trafficserver,persiaAziz/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,dyrock/trafficserver,duke8253/trafficserver,davidbz/trafficserver,persiaAziz/trafficserver,persiaAziz/trafficserver,vmamidi/trafficserver,chitianhao/trafficserver,dyrock/trafficserver,SolidWallOfCode/trafficserver,davidbz/trafficserver,davidbz/trafficserver,bryancall/trafficserver,chitianhao/trafficserver,pbchou/trafficserver,dyrock/trafficserver,SolidWallOfCode/trafficserver,chitianhao/trafficserver,pbchou/trafficserver,duke8253/trafficserver,vmamidi/trafficserver,vmamidi/trafficserver,vmamidi/trafficserver,persiaAziz/trafficserver,davidbz/trafficserver,pbchou/trafficserver,persiaAziz/trafficserver,chitianhao/trafficserver,pbchou/trafficserver,bryancall/trafficserver,duke8253/trafficserver,persiaAziz/trafficserver,davidbz/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,duke8253/trafficserver,vmamidi/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver,davidbz/trafficserver,pbchou/trafficserver,dyrock/trafficserver,pbchou/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,chitianhao/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver,SolidWallOfCode/trafficserver,chitianhao/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,duke8253/trafficserver,duke8253/trafficserver