pig-latin: improve documentation (#1171)
pig-latin: improve documentation (#1171)

* add more rules to the pig latin exercise to help make it clearer

* made suggested updates to rules

* apply proposed changes to clarify the rules

ErikSchierboom/x-common,exercism/x-common,jmluy/x-common,rpottsoh/x-common,exercism/x-common,jmluy/x-common,petertseng/x-common,ErikSchierboom/x-common,jmluy/x-common,rpottsoh/x-common,petertseng/x-common