Remove #with_index call and manually calculate index
Remove #with_index call and manually calculate index

This reduces mamory usage by about 6%:
  https://gist.github.com/yuki24/21f40d10bdae7c2a3e91/f79dde5c85c7db242b34bae04e1f73d466e823e1

Ye-Yong-Chi/did_you_mean,yuki24/did_you_mean,yui-knk/did_you_mean