update redirect from /esnext to /es2016plus for old (ES7) references
update redirect from /esnext to /es2016plus for old (ES7) references

Because it fits better for ES7 after moving es201x specs to separate tab in #827
mzgol/compat-table,mzgol/compat-table,Delapouite/compat-table,Delapouite/compat-table,KTamas/compat-table,KTamas/compat-table