Index existing #| and #= declarator block documentation.
Index existing #| and #= declarator block documentation.

(Partially addresses #2305.)

tbrowder/doc,tbrowder/doc,MasterDuke17/doc,perl6/doc,MasterDuke17/doc,perl6/doc,MasterDuke17/doc,perl6/doc,tbrowder/doc,perl6/doc,perl6/doc,MasterDuke17/doc,tbrowder/doc