fix: Safari scrollTop

[malinbranduse]

direction="top" on Safari was not preserving scroll after prepending new items because scrollTop is always 0 on the body in Safari. Tracked it down to this small little tweak. Tested on Chrome and Safari.

[codecov[bot]]

Codecov Report

Merging #243 into master will not change coverage. The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #243   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            5         5           
  Lines          174       174           
  Branches        32        32           
=========================================
  Hits           174       174           

Impacted Files	Coverage Δ
src/utils.js	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update ccf1a20...2697b15. Read the comment docs.

[re757575]

It works for me #256, but is document.scrollingElement