Unable to specify category separators

[tillik]

Just tried out github-wiki-sidebar in enquire-mode and am unable to specify a category separator.

I am always being prompted that "The following characters are allowed a-z#~ @_!" rregardless if I try to choose the default (just hitting enter) or manually defining a category separator.

(Running this within the latest PowerShell Core 6.2.2)

Originally posted by @tillik in https://github.com/adriantanasa/github-wiki-sidebar/issues/5#issuecomment-558550284