* doc/syntax/literals.rdoc (Strings): mention about ?a literal.

	literals.rdoc: fix typos

	* doc/syntax/literals.rdoc (Strings): fix typos.
	* doc/syntax/literals.rdoc (Strings): [DOC] Document the full list
	  of supported escape sequences in string literals.

	* doc/syntax/literals.rdoc (Strings): [DOC] Revise the character
	  literal part.

	literals.rdoc: add DEL [ci skip]

	* doc/syntax/literals.rdoc (Strings): [DOC] add DEL.
	[DOC] `\0` is interpreted as NUL only if not followed by an octal digit.
	[DOC] Remove `\0` since it's aprt of octal notation

	A typo is fixed while at it.
	doc: Fix error for escape sequences in string literals

	Backslash goes first in escape sequences, so it must be
	"any other character following a backslash is interpreted as ...",
	while the doc says "...followed by...".

	Author: Marcus Stollsteimer <sto.mar@web.de>
	[ruby-core:79418] [Bug #13190]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@58114 b2dd03c8-39d4-4d8f-98ff-823fe69b080e