[Report] join[|] filter operator produces error "Filter error: Missing closing bracket in filter expression"

In a new tiddler, enter `{{{ a b c +[join[-]] }}}`, result is `a-b-c` Change filter to `{{{ a b c +[join[|]] }}}`, result is "Filter error: Missing closing bracket in filter expression" Work around: `<$let sep="|">{{{ a b c +[join<sep>] }}}`, result is `a|b|c` Testing shows this error goes all the way back to v5.1.0, so it probably can't be fixed now, but should be noted in documentation for https://tiddlywiki.com/#join%20Operator