Update sbt-scalafix to 0.9.18

[scala-steward]

Updates ch.epfl.scala:sbt-scalafix from 0.9.17 to 0.9.18.
GitHub Release Notes - Version Diff

I'll automatically update this PR to resolve conflicts as long as you don't change it yourself.

If you'd like to skip this version, you can just close this PR. If you have any feedback, just mention me in the comments below.

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Ignore future updates

Add this to your .scala-steward.conf file to ignore future updates of this dependency:

updates.ignore = [ { groupId = "ch.epfl.scala", artifactId = "sbt-scalafix" } ]

labels: sbt-plugin-update, semver-patch

[codecov-commenter]

Codecov Report

Merging #3506 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3506   +/-   ##
=======================================
  Coverage   91.75%   91.75%           
=======================================
  Files         383      383           
  Lines        8406     8406           
  Branches      212      212           
=======================================
  Hits         7713     7713           
  Misses        693      693