docs(helm): fix duplicated anchor ids

Created by: michaellzc

We have a lot of headers with the same text, so we need to manually configure the id (?) of the header. Otherwise, http://localhost:5080/admin/install/kubernetes/helm#steps will bring users to no where

Test plan

sg run docsite

Visit http://localhost:5080/admin/install/kubernetes/helm#eks-steps and it should bring you to eks steps