Add CSS rule for c-Singleline
Add CSS rule for c-Singleline

Due a bug in the Perl 6 pygments lexer, single line comments
are given a CSS class that doesn't exist in the normal set
of classes that pygments provides.  This will allow single-line
comments to be highlighted until that bug is fixed

tbrowder/doc,stmuk/doc,stmuk/doc,MasterDuke17/doc,tbrowder/doc,gfldex/doc,MasterDuke17/doc,jkeenan/doc,dha/doc,gfldex/doc,stmuk/doc,stmuk/doc,MadcapJake/doc,dha/doc,jonathanstowe/doc,dnmfarrell/doc,gfldex/doc,muraiki/doc,MadcapJake/doc,muraiki/doc,dmaestro/doc,MadcapJake/doc,muraiki/doc,dha/doc,dha/doc,hoelzro/perl6-doc,hoelzro/perl6-doc,cygx/doc,jonathanstowe/doc,jkeenan/doc,dmaestro/doc,cygx/doc,LLFourn/doc,cygx/doc,muraiki/doc,gfldex/doc,jkeenan/doc,dnmfarrell/doc,jonathanstowe/doc,antquinonez/doc,stmuk/doc,cygx/doc,dnmfarrell/doc,muraiki/doc,hoelzro/perl6-doc,MasterDuke17/doc,perl6/doc,antquinonez/doc,dmaestro/doc,tbrowder/doc,perl6/doc,jkeenan/doc,jonathanstowe/doc,antquinonez/doc,MadcapJake/doc,dmaestro/doc,perl6/doc,LLFourn/doc,LLFourn/doc,antquinonez/doc,dmaestro/doc,dha/doc,MadcapJake/doc,dnmfarrell/doc,dnmfarrell/doc,hoelzro/perl6-doc,LLFourn/doc,gfldex/doc,tbrowder/doc,LLFourn/doc,antquinonez/doc,cygx/doc,jkeenan/doc,perl6/doc,jonathanstowe/doc,perl6/doc,hoelzro/perl6-doc,MasterDuke17/doc