Fix mistake in BUILDALL example code
Fix mistake in BUILDALL example code

Immediate `nextsame` makes a method a no op. Switched to `callsame`. This revealed that the BUILDALL example failed to return `self`.
perl6/doc,MasterDuke17/doc,jonathanstowe/doc,jonathanstowe/doc,jonathanstowe/doc,antquinonez/doc,tbrowder/doc,gfldex/doc,dmaestro/doc,gfldex/doc,jonathanstowe/doc,antquinonez/doc,stmuk/doc,perl6/doc,dmaestro/doc,perl6/doc,jonathanstowe/doc,antquinonez/doc,perl6/doc,dmaestro/doc,antquinonez/doc,dmaestro/doc,MasterDuke17/doc,gfldex/doc,dha/doc,stmuk/doc,tbrowder/doc,gfldex/doc,dha/doc,stmuk/doc,MasterDuke17/doc,stmuk/doc,stmuk/doc,MasterDuke17/doc,dha/doc,perl6/doc,dmaestro/doc,antquinonez/doc,dha/doc,gfldex/doc,tbrowder/doc,dha/doc,tbrowder/doc