Should std.conv:parse parse html entities?

[berni44]

Concerning issue 9621 [1]: There are two things, that parse 
doesn't parse currently, namely octal numbers and html entities. 
While there is no argument against the former (I actually wrote a 
PR to add them), there has been some discussion around the later, 
because the whole table of those entities (about 3000) would make 
it in the code, even if not needed at all.

As I don't think, I should try to decide this on my own, I'd like 
to know your oppinion: What is better: Add the entities or write 
in the docs, that they are not supported? What do you think?

[1] https://issues.dlang.org/show_bug.cgi?id=9621