replace and/or operators w/ &&/|| (when not used for control flow)

Because and/or are for control flow, &&/|| for logic; the precedence is quite different.

e.g. or has lower precedence than =:

irb> a = false || true # a = (false || true)
=> true
irb> a
=> true
irb> a = false or true # (a = false) or true
=> true
irb> a
=> false