changed backticks to single quotes to be consistent with the rest of the doc.
changed backticks to single quotes to be consistent with the rest of the doc.

forwchen/yt8m,slai11/youtube-8m,KangHsi/youtube-8m,hxkk/u8m_test,forwchen/yt8m,coded5282/youtube-8m,slai11/youtube-8m,slai11/youtube-8m,google/youtube-8m,lidalei/youtube-8m,KangHsi/youtube-8m,mwoodson1/youtube-8m-competition,slai11/youtube-8m