message: Fix typo in XLA's Gather documentation.
diff: @@ -1481,8 +1481,8 @@ The element in the output array at index
  [`G`,`O`<sub>`0`</sub>,`O`<sub>`1`</sub>] is then the element in the input
  array at index [`X`+`O`<sub>`0`</sub>,`Y`+`O`<sub>`1`</sub>].
  -`slice_sizes` is `[8,6]`, which decides the range of W<sub>`0`</sub> and
  -W<sub>`1`</sub>, and this in turn decides the bounds of the slice.
  +`slice_sizes` is `[8,6]`, which decides the range of O<sub>`0`</sub> and
  +O<sub>`1`</sub>, and this in turn decides the bounds of the slice.
  This gather operation acts as a batch dynamic slice with `G` as the batch
  dimension.
  