instrumenting: add Rust client library link.
instrumenting: add Rust client library link.
du2016/prometheus-docs,chosenken/docs,tcolgate/docs,tcolgate/docs,open-falcon/open-falcon.github.io,du2016/prometheus-docs,chosenken/docs,tcolgate/docs,open-falcon/open-falcon.github.io,Cepave/openfalcon.io,chosenken/docs,du2016/prometheus-docs,prometheus/docs,Cepave/openfalcon.io,Cepave/openfalcon.io,ddfreyne/prometheus-docs,ddfreyne/prometheus-docs,prometheus/docs,prometheus/docs,chosenken/docs,ddfreyne/prometheus-docs,ddfreyne/prometheus-docs,open-falcon/open-falcon.github.io