fix a bug in retrieving prefixes from QuranyCorpus words
fix a bug in retrieving prefixes from QuranyCorpus words

Former-commit-id: d1ba76ae9ed6627cef11ced69866c2a496ddede5
muslih/alfanous,muslih/alfanous,muslih/alfanous,muslih/alfanous,muslih/alfanous,muslih/alfanous,muslih/alfanous