Remove incorrect about incorrect usage of \x in strings

Their usage in Elixir v1.0 was always semantically wrong,
which became deprecation warnings in v1.1 to avoid crashes.
Any software relying on this feature both emits warnings
and invalid strings.

Closes elixir-lang#14660.

Author: josevalim

lib/elixir/src/elixir_interpolation.erl

@@ -208,36 +208,6 @@ unescape_hex(<<A, B, Rest/binary>>, Map, Acc) when ?is_hex(A), ?is_hex(B) ->
   Bytes = list_to_integer([A, B], 16),
   unescape_chars(Rest, Map, <<Acc/binary, Bytes>>);
 
-%% TODO: Remove deprecated sequences on v2.0
-
-unescape_hex(<<A, Rest/binary>>, Map, Acc) when ?is_hex(A) ->
-  io:format(standard_error, "warning: \\xH inside strings/sigils/chars is deprecated, please use \\xHH (byte) or \\uHHHH (code point) instead~n", []),
-  append_codepoint(Rest, Map, [A], Acc, 16);
-
-unescape_hex(<<${, A, $}, Rest/binary>>, Map, Acc) when ?is_hex(A) ->
-  io:format(standard_error, "warning: \\x{H*} inside strings/sigils/chars is deprecated, please use \\xHH (byte) or \\uHHHH (code point) instead~n", []),
-  append_codepoint(Rest, Map, [A], Acc, 16);
-
-unescape_hex(<<${, A, B, $}, Rest/binary>>, Map, Acc) when ?is_hex(A), ?is_hex(B) ->
-  io:format(standard_error, "warning: \\x{H*} inside strings/sigils/chars is deprecated, please use \\xHH (byte) or \\uHHHH (code point) instead~n", []),
-  append_codepoint(Rest, Map, [A, B], Acc, 16);
-
-unescape_hex(<<${, A, B, C, $}, Rest/binary>>, Map, Acc) when ?is_hex(A), ?is_hex(B), ?is_hex(C) ->
-  io:format(standard_error, "warning: \\x{H*} inside strings/sigils/chars is deprecated, please use \\xHH (byte) or \\uHHHH (code point) instead~n", []),
-  append_codepoint(Rest, Map, [A, B, C], Acc, 16);
-
-unescape_hex(<<${, A, B, C, D, $}, Rest/binary>>, Map, Acc) when ?is_hex(A), ?is_hex(B), ?is_hex(C), ?is_hex(D) ->
-  io:format(standard_error, "warning: \\x{H*} inside strings/sigils/chars is deprecated, please use \\xHH (byte) or \\uHHHH (code point) instead~n", []),
-  append_codepoint(Rest, Map, [A, B, C, D], Acc, 16);
-
-unescape_hex(<<${, A, B, C, D, E, $}, Rest/binary>>, Map, Acc) when ?is_hex(A), ?is_hex(B), ?is_hex(C), ?is_hex(D), ?is_hex(E) ->
-  io:format(standard_error, "warning: \\x{H*} inside strings/sigils/chars is deprecated, please use \\xHH (byte) or \\uHHHH (code point) instead~n", []),
-  append_codepoint(Rest, Map, [A, B, C, D, E], Acc, 16);
-
-unescape_hex(<<${, A, B, C, D, E, F, $}, Rest/binary>>, Map, Acc) when ?is_hex(A), ?is_hex(B), ?is_hex(C), ?is_hex(D), ?is_hex(E), ?is_hex(F) ->
-  io:format(standard_error, "warning: \\x{H*} inside strings/sigils/chars is deprecated, please use \\xHH (byte) or \\uHHHH (code point) instead~n", []),
-  append_codepoint(Rest, Map, [A, B, C, D, E, F], Acc, 16);
-
 unescape_hex(<<_/binary>>, _Map, _Acc) ->
   throw({error, "invalid hex escape character, expected \\xHH where H is a hexadecimal digit", "\\x"}).