Re-enable ability to override icons in "Topics" section#939

mportiz08 wants to merge 2 commits intoswiftlang:mainswiftlang/swift-docc-render:mainfrom

mportiz08:reenable-icon-overrides-in-topics-sectionmportiz08/swift-docc-render:reenable-icon-overrides-in-topics-sectionCopy head branch name to clipboard