Stop signaling an error when reading "smart quotes" in symbols

Stop signaling an error when reading "smart quotes" in symbols

Revert commits from 2018-01-28 "Fix round tripping of read->print for
symbols with strange quotes", and 2017-07-22 "Signal error for symbol
names with strange quotes (Bug#2967)".
* etc/NEWS: Remove corresponding entries.
* src/character.c (confusable_symbol_character_p):
* test/src/lread-tests.el (lread-tests--old-style-backquotes): Remove.
* src/lread.c (read1): Don't signal error on confusable character.
* src/print.c (print_object): Don't escape confusable characters.