Add some new expression doc sections
Add some new expression doc sections

sschnug/pyeda,sschnug/pyeda,cjdrake/pyeda,sschnug/pyeda,pombredanne/pyeda,GtTmy/pyeda,cjdrake/pyeda,GtTmy/pyeda,karissa/pyeda,karissa/pyeda,GtTmy/pyeda,pombredanne/pyeda,karissa/pyeda,cjdrake/pyeda,pombredanne/pyeda