Formatter: escape bi-directional control characters within strings

[HertzDevil]

This patch makes the formatter escape Unicode bi-directional control characters that appear in the following contexts (where 😂 is any of the control characters):

"😂"
"😂#{1}"
%(😂)
%Q(😂)

<<-EOS
😂
EOS

<<-EOS
😂#{1}
EOS

def foo("😂" x)
end

foo("😂": 1)
NamedTuple("😂": Int32)
{"😂": 1}

It does not cover symbol literals yet.

See #11392 and #12923.