Fix: digits should not include underscore
@@ -233,13 +233,13 @@ literal_. The grammar for recognizing the two kinds of literals is mixed.
> HEX_LITERAL :
> &nbsp;&nbsp; `0x` (HEX_DIGIT|`_`)<sup>\*</sup> HEX_DIGIT (HEX_DIGIT|`_`)<sup>\*</sup>
>
-> BIN_DIGIT : [`0`-`1` `_`]
+> BIN_DIGIT : [`0`-`1`]
>
-> OCT_DIGIT : [`0`-`7` `_`]
+> OCT_DIGIT : [`0`-`7`]
>
-> DEC_DIGIT : [`0`-`9` `_`]
+> DEC_DIGIT : [`0`-`9`]
>
-> HEX_DIGIT : [`0`-`9` `a`-`f` `A`-`F` `_`]
+> HEX_DIGIT : [`0`-`9` `a`-`f` `A`-`F`]
>
> INTEGER_SUFFIX :
> &nbsp;&nbsp; &nbsp;&nbsp; `u8` | `u16` | `u32` | `u64` | `usize`
