Change install instructions to suppress curl output
Change install instructions to suppress curl output

This is here in the event that you decide to merge
https://github.com/exercism/cli-www/pull/14 into the CLI. You can see a
screenshot of the overall change in that PR.

ZacharyRSmith/docs,yurrriq/docs,rchavarria/docs,k4rtik/docs,yurrriq/docs,exercism/DEPRECATED.help.exercism.io,lfex/exercism-docs,NobbZ/docs,arashbi/docs,ZacharyRSmith/docs,rchavarria/docs,ekse/exercism-docs,alexclarkofficial/docs,arashbi/docs,lfex/exercism-docs,spazm/docs,spazm/docs,canweriotnow/docs,k4rtik/docs,ekse/exercism-docs,canweriotnow/docs,alexclarkofficial/docs,NobbZ/docs,exercism/DEPRECATED.help.exercism.io