Make reference to a class in the description valid
Make reference to a class in the description valid

Closes https://github.com/perl6/doc/issues/979; payerle++
MasterDuke17/doc,perl6/doc,jonathanstowe/doc,stmuk/doc,perl6/doc,perl6/doc,gfldex/doc,antquinonez/doc,dmaestro/doc,tbrowder/doc,stmuk/doc,stmuk/doc,antquinonez/doc,antquinonez/doc,antquinonez/doc,gfldex/doc,perl6/doc,jonathanstowe/doc,tbrowder/doc,gfldex/doc,gfldex/doc,jonathanstowe/doc,tbrowder/doc,jonathanstowe/doc,dmaestro/doc,dmaestro/doc,MasterDuke17/doc,MasterDuke17/doc,gfldex/doc,antquinonez/doc,stmuk/doc,MasterDuke17/doc,dmaestro/doc,perl6/doc,stmuk/doc,dmaestro/doc,tbrowder/doc,jonathanstowe/doc