docs mention for 12188. refer to correct component

BS3 commits: 17f2ef46aa68319668ed36f846fc72027b79afda,
b192d29981a394ea7c7f390d926cedeb8887062f
Fixes 12171: Ensure panel groups have a bottom margin since we nuke it on child panels

BS3 commits: 3a8e99e91eeb03d72c0a015de16f743dd5335312