raft: delete unused Ready.containsUpdates method

[nvb]

The function was unused beyond its own unit test. Delete it.

Signed-off-by: Nathan VanBenschoten nvanbenschoten@gmail.com

Extracted from #14627. cc. @tbg

Please read https://github.com/etcd-io/etcd/blob/main/CONTRIBUTING.md#contribution-flow.

[codecov-commenter]

Codecov Report

Merging #14722 (0bff3ad) into main (0bff3ad) will not change coverage.
The diff coverage is n/a.

❗ Current head 0bff3ad differs from pull request most recent head e0beef6. Consider uploading reports for the commit e0beef6 to get more accurate results

@@           Coverage Diff           @@
##             main   #14722   +/-   ##
=======================================
  Coverage   75.58%   75.58%           
=======================================
  Files         457      457           
  Lines       37323    37323           
=======================================
  Hits        28211    28211           
  Misses       7342     7342           
  Partials     1770     1770           

Flag	Coverage Δ
all	75.58% <0.00%> (ø)

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[ahrtr]

LGTM

[ahrtr]

Always good to see code cleanup. Thank you @nvanbenschoten