missing HexString documentation

[Seb]

On Wednesday, 7 February 2018 at 15:25:05 UTC, Steven 
Schveighoffer wrote:
> On 2/7/18 9:59 AM, Ralph Doncaster wrote:
>> It is mentioned in the literals section, but not documented:
>> https://dlang.org/spec/lex.html#string_literals
>> 
>>  From reading forum posts I managed to figure out that 
>> HexStrings are prefixed with an x.  i.e. x"deadbeef"
>> 
>
> Good catch! Even the grammar says nothing about what it is, 
> except it has HexString as a possible literal.
>
> Can you file an issue? https://issues.dlang.org
>
> -Steve

They are deprecated:

https://dlang.org/changelog/pending.html#hexstrings
https://dlang.org/deprecate.html#Hexstring%20literals

Hence, the grammar has been incompletely updated. As it's not an 
error to use them now, it should have stated that they are 
deprecated.

Anyhow, you can always go back in time:

https://docarchives.dlang.io/v2.078.0/spec/lex.html#HexString