Fixes image links
Fixes image links

There were two broken links to Xamarin setup/testing.
ZacharyRSmith/docs,exercism/DEPRECATED.help.exercism.io,rchavarria/docs,ZacharyRSmith/docs,lfex/exercism-docs,exercism/DEPRECATED.help.exercism.io,spazm/docs,lfex/exercism-docs,spazm/docs,rchavarria/docs