Mention single-quotes

Author: Denton-L

docs/types.rst

@@ -214,9 +214,9 @@ a non-rational number).
 String Literals
 ---------------
 
-String Literals are written with double quotes (``"abc"``). As with integer literals, their type can vary, but they are implicitly convertible to ``bytes1``, ..., ``bytes32`` if they fit, to ``bytes`` and to ``string``.
+String literals are written with either double or single-quotes (``"foo"`` or ``'bar'``). As with integer literals, their type can vary, but they are implicitly convertible to ``bytes1``, ..., ``bytes32``, if they fit, to ``bytes`` and to ``string``.
 
-String Literals support escape characters, such as ``\n``, ``\xNN`` and ``\uNNNN``. ``\xNN`` takes a hex value and inserts the appropriate byte, while ``\uNNNN`` takes a Unicode codepoint and inserts an UTF-8 sequence.
+String literals support escape characters, such as ``\n``, ``\xNN`` and ``\uNNNN``. ``\xNN`` takes a hex value and inserts the appropriate byte, while ``\uNNNN`` takes a Unicode codepoint and inserts an UTF-8 sequence.
 
 .. index:: enum