[doc://perlsub#Subroutine-Attributes-attribute-subroutine,-attribute-attrs|Subroutine attributes] gives the link: Subroutine attributes.

The easiest way to "discover" the link is to point your browser to perlsub, then click the TOC entry for the section you want to link to. The link can then be copied from the browser and the encoded characters cleaned up (maybe one day PM will handle the encoded chars so cleaning up's not needed).