Remove faulty paragraph about plugin configs.
Remove faulty paragraph about plugin configs.

The dev-plugins documentation states:

"The plugin configuration is loaded only once and is then cached.
Similar to changes in 'gerrit.config', changes to the plugin
configuration file will only become effective after a Gerrit restart."

This is not true anymore:

“Flush global plugin config on plugin reload”
https://gerrit-review.googlesource.com/#/c/52524/

“Allow plugins to check for config updates when reading plugin config”
https://gerrit-review.googlesource.com/#/c/54060/

Change-Id: Iac588f1ff7b00ab47e084129a532edd5cf636c4f

renchaorevee/gerrit,anminhsu/gerrit,gcoders/gerrit,Seinlin/gerrit,supriyantomaftuh/gerrit,netroby/gerrit,hdost/gerrit,GerritCodeReview/gerrit,quyixia/gerrit,dwhipstock/gerrit,netroby/gerrit,renchaorevee/gerrit,Seinlin/gerrit,qtproject/qtqa-gerrit,joshuawilson/merrit,Distrotech/gerrit,renchaorevee/gerrit,hdost/gerrit,dwhipstock/gerrit,TonyChai24/test,quyixia/gerrit,supriyantomaftuh/gerrit,renchaorevee/gerrit,TonyChai24/test,gerrit-review/gerrit,jackminicloud/test,hdost/gerrit,anminhsu/gerrit,pkdevbox/gerrit,Seinlin/gerrit,jackminicloud/test,joshuawilson/merrit,Distrotech/gerrit,qtproject/qtqa-gerrit,quyixia/gerrit,thinkernel/gerrit,thesamet/gerrit,TonyChai24/test,Distrotech/gerrit,MerritCR/merrit,WANdisco/gerrit,renchaorevee/gerrit,hdost/gerrit,WANdisco/gerrit,gerrit-review/gerrit,joshuawilson/merrit,anminhsu/gerrit,gcoders/gerrit,gerrit-review/gerrit,gcoders/gerrit,Overruler/gerrit,gcoders/gerrit,quyixia/gerrit,quyixia/gerrit,GerritCodeReview/gerrit,thesamet/gerrit,gcoders/gerrit,Overruler/gerrit,pkdevbox/gerrit,MerritCR/merrit,netroby/gerrit,TonyChai24/test,qtproject/qtqa-gerrit,jackminicloud/test,joshuawilson/merrit,Seinlin/gerrit,WANdisco/gerrit,thinkernel/gerrit,WANdisco/gerrit,gerrit-review/gerrit,Overruler/gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,dwhipstock/gerrit,Overruler/gerrit,hdost/gerrit,renchaorevee/gerrit,supriyantomaftuh/gerrit,qtproject/qtqa-gerrit,joshuawilson/merrit,pkdevbox/gerrit,MerritCR/merrit,GerritCodeReview/gerrit,quyixia/gerrit,dwhipstock/gerrit,supriyantomaftuh/gerrit,GerritCodeReview/gerrit,Distrotech/gerrit,supriyantomaftuh/gerrit,Overruler/gerrit,netroby/gerrit,pkdevbox/gerrit,Seinlin/gerrit,pkdevbox/gerrit,MerritCR/merrit,thinkernel/gerrit,joshuawilson/merrit,pkdevbox/gerrit,TonyChai24/test,GerritCodeReview/gerrit,netroby/gerrit,gerrit-review/gerrit,WANdisco/gerrit,anminhsu/gerrit,Distrotech/gerrit,thesamet/gerrit,dwhipstock/gerrit,MerritCR/merrit,Seinlin/gerrit,Distrotech/gerrit,thesamet/gerrit,joshuawilson/merrit,jackminicloud/test,jackminicloud/test,gcoders/gerrit,thinkernel/gerrit,TonyChai24/test,thinkernel/gerrit,supriyantomaftuh/gerrit,jackminicloud/test,MerritCR/merrit,Distrotech/gerrit,dwhipstock/gerrit,jackminicloud/test,anminhsu/gerrit,netroby/gerrit,Seinlin/gerrit,Overruler/gerrit,GerritCodeReview/gerrit,dwhipstock/gerrit,thesamet/gerrit,supriyantomaftuh/gerrit,thinkernel/gerrit,WANdisco/gerrit,thesamet/gerrit,qtproject/qtqa-gerrit,MerritCR/merrit,WANdisco/gerrit,TonyChai24/test,GerritCodeReview/gerrit,netroby/gerrit,gerrit-review/gerrit,quyixia/gerrit,thinkernel/gerrit,gcoders/gerrit,renchaorevee/gerrit,joshuawilson/merrit,thesamet/gerrit,hdost/gerrit,hdost/gerrit,MerritCR/merrit,pkdevbox/gerrit,GerritCodeReview/gerrit,anminhsu/gerrit,gerrit-review/gerrit,anminhsu/gerrit