Updated mediawiki/extensions Project: mediawiki/extensions/Collection b401b191e0bbce991bb3015b22e9df59d266955f
Remove $wgCollectionHierarchyDelimiter workaround.
This is a breaking change for wikis using non-standard delimiters or
relying on pseudo-subpages without actually setting them as subpages,
but no such wiki is known (for instance Wikibooks uses the delimiter,
but also uses subpages).
This patch was forked from Federico Leva's work in
https://gerrit.wikimedia.org/r/163139, including some of his
improvements to code comments and type safety.