Update v0.21.0.txt

Author: TomAugspurger

doc/source/whatsnew/v0.21.0.txt

@@ -588,9 +588,6 @@ Indexing
 - Bug in ``CategoricalIndex`` reindexing in which specified indices containing duplicates were not being respected (:issue:`17323`)
 - Bug in intersection of ``RangeIndex`` with negative step (:issue:`17296`)
 - Bug in ``IntervalIndex`` where performing a scalar lookup fails for included right endpoints of non-overlapping monotonic decreasing indexes (:issue:`16417`, :issue:`17271`)
-<<<<<<< f97c9bc2d44f7aa58314fe67f1fa074af3032473
-<<<<<<< 4996e764fb0adbd5c77574eb3cb60f19c0fafba3
-<<<<<<< 99300ddcc636c859a02b3010ee379d1adbd1678e
 - Bug in :meth:`DataFrame.first_valid_index` and :meth:`DataFrame.last_valid_index` when no valid entry (:issue:`17400`)
 - Bug in :func:`Series.rename` when called with a `callable`, incorrectly alters the name of the `Series`, rather than the name of the `Index`. (:issue:`17407`)