Improve wording in the naming section even more.
Improve wording in the naming section even more.

This should have been part of
https://github.com/prometheus/docs/pull/95, but somehow I missed to
commit it.

dato/prometheus-docs,du2016/prometheus-docs,evanphx/docs,tcolgate/docs,evanphx/docs,open-falcon/open-falcon.github.io,vic3lord/docs,chosenken/docs,jimmidyson/docs,jimmidyson/docs,vic3lord/docs,ddfreyne/prometheus-docs,ChaoticMind/docs,open-falcon/open-falcon.github.io,chosenken/docs,tcolgate/docs,dato/prometheus-docs,Cepave/openfalcon.io,prometheus/docs,ddfreyne/prometheus-docs,chosenken/docs,jmptrader/docs,ddfreyne/prometheus-docs,dato/prometheus-docs,ChaoticMind/docs,tcolgate/docs,open-falcon/open-falcon.github.io,jmptrader/docs,jmptrader/docs,ddfreyne/prometheus-docs,du2016/prometheus-docs,Cepave/openfalcon.io,fabxc/docs,dln/docs,ChaoticMind/docs,pdbogen/docs,dln/docs,bluecmd/prometheus-docs,bluecmd/prometheus-docs,evanphx/docs,jimmidyson/docs,fabxc/docs,pdbogen/docs,prometheus/docs,dln/docs,fabxc/docs,Cepave/openfalcon.io,du2016/prometheus-docs,chosenken/docs,pdbogen/docs,vic3lord/docs,bluecmd/prometheus-docs,prometheus/docs