Update description of @-0, @-N, and @+N.
Update description of @-0, @-N, and @+N.

xmirror/m17n-db,sanskrit-coders/m17n-db,sanskrit-coders/m17n-db,xmirror/m17n-db,xmirror/m17n-db,xmirror/m17n-db,sanskrit-coders/m17n-db