octal: Remove Ruby-specific terms
octal: Remove Ruby-specific terms

These descriptions need to be language-agnostic since they are shown for
each language. #100 did the same for hexadecimal.

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