Backport patches from ruby/ruby#2

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hsbt merged 2 commits intomasterfrom

backport-ruby-core

Nov 27, 2018

Commits on Nov 27, 2018

lib/*: Prefer require_relative over require.

marcandre
authored and
hsbt
committed
lib/*: Prefer require_relative over require, remove explicit extension

marcandre
authored and
hsbt
committed