Amended hello-world/description.md to be formatted to 80 chars.
Amended hello-world/description.md to be formatted to 80 chars.

Should allow reading of the rendered README.md easier if viewing in a
restricted window.

rpottsoh/x-common,jmluy/x-common,petertseng/x-common,ErikSchierboom/x-common,rpottsoh/x-common,kgengler/x-common,exercism/x-common,kgengler/x-common,petertseng/x-common,ErikSchierboom/x-common,Vankog/problem-specifications,jmluy/x-common,exercism/x-common,Vankog/problem-specifications,jmluy/x-common