add precedence for infix `div` and `mod`
add precedence for infix `div` and `mod`

These functions have the same precedence as `/`.

kojiromike/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev