eval_error.c: rb_error_write flags

	* eval_error.c (rb_error_write): add highlight and reverse mode
	  flags.  defaulted to rb_stderr_tty_p() if Qnil.

	error.c: full_message options

	* error.c (exc_full_message): add highlight: and reverse: keyword
	  options.  [Bug #14324]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@62905 b2dd03c8-39d4-4d8f-98ff-823fe69b080e