Fix run-on sentence, improve increase() doc wording.
Fix run-on sentence, improve increase() doc wording.

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