Byte literal syntax: add missing quote escapes

Current definitions of byte character literals do not allow escaped
single quotes and byte string literals do not allow escape double
quotes. Updated lexical syntax for byte characters and strings to allow
these characters. This is in sync with the implementation.

src/tokens.md

@@ -228,7 +228,7 @@ r##"foo #"# bar"##;                // foo #"# bar
 
 > **<sup>Lexer</sup>**\
 > BYTE_LITERAL :\
-> &nbsp;&nbsp; `b'` ( ASCII_FOR_CHAR | BYTE_ESCAPE )  `'`
+> &nbsp;&nbsp; `b'` ( ASCII_FOR_CHAR | BYTE_ESCAPE | `\'` )  `'`
 >
 > ASCII_FOR_CHAR :\
 > &nbsp;&nbsp; _any ASCII (i.e. 0x00 to 0x7F), except_ `'`, `\`, \\n, \\r or \\t
@@ -248,7 +248,7 @@ _number literal_.
 
 > **<sup>Lexer</sup>**\
 > BYTE_STRING_LITERAL :\
-> &nbsp;&nbsp; `b"` ( ASCII_FOR_STRING | BYTE_ESCAPE | STRING_CONTINUE )<sup>\*</sup> `"`
+> &nbsp;&nbsp; `b"` ( ASCII_FOR_STRING | BYTE_ESCAPE | STRING_CONTINUE | `\"` )<sup>\*</sup> `"`
 >
 > ASCII_FOR_STRING :\
 > &nbsp;&nbsp; _any ASCII (i.e 0x00 to 0x7F), except_ `"`, `\` _and IsolatedCR_