Fix link to Custom Serializer section
Fix link to Custom Serializer section

Looks like the heading changed at some point, not allowing one to easily click down to that section
theRealNG/paper_trail,airblade/paper_trail,ifeelgoods/paper_trail,jnstq/paper_trail,ifeelgoods/paper_trail,jnstq/paper_trail,devonestes/paper_trail,airblade/paper_trail,theRealNG/paper_trail