Fix: return unsorted array element in quantile function

[wujunfu]

Changelog category (leave one):

• Bug Fix (user-visible misbehavior in official stable or prestable release)

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Fix functions (quantilesExactExclusive, quantilesExactInclusive) return unsorted array element.

[CLAassistant]

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[wujunfu]

@CurtizJ @serxa
Hi, could you help me add "can be tested" label ?

[yakov-olkhovskiy]

@wujunfu nice catch, though std::max_element std::mix_element return iterator - you need to dereference it...