Update sbt-mdoc to 2.5.3

Author: scala-steward

project/plugins.sbt

@@ -1,7 +1,7 @@
 addSbtPlugin("com.geirsson"              % "sbt-ci-release"  % "1.5.7")
 addSbtPlugin("com.typesafe"              % "sbt-mima-plugin" % "0.8.1")
 addSbtPlugin("io.github.davidgregory084" % "sbt-tpolecat"    % "0.1.17")
-addSbtPlugin("org.scalameta"             % "sbt-mdoc"        % "2.2.20")
+addSbtPlugin("org.scalameta"             % "sbt-mdoc"        % "2.5.3")
 addSbtPlugin("org.scalameta"             % "sbt-scalafmt"    % "2.4.2")
 addSbtPlugin("org.scoverage"             % "sbt-scoverage"   % "1.6.1")
 addSbtPlugin("ch.epfl.scala"             % "sbt-scalafix"    % "0.9.27")