BUG: tslib.tzconvert handles DST incorrectly
DOC: grammar fixes in docs
Merge pull request #7906 from mortada/grammar

DOC: grammar fixes in docs
Merge pull request #7798 from sinhrks/tz_convert_bug

BUG: tslib.tz_convert and tslib.tz_convert_single may output different result in DST
ENH: Add BusinessHour offset