Update mdoc, sbt-mdoc to 2.5.1

Author: scala-steward

project/plugins.sbt

@@ -2,5 +2,5 @@ addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "3.9.21")
 addSbtPlugin("com.github.sbt" % "sbt-pgp"      % "2.1.2")
 addSbtPlugin("org.scalameta"  % "sbt-scalafmt" % "2.5.2")
 addSbtPlugin("com.github.sbt" % "sbt-release"  % "1.1.0")
-addSbtPlugin("org.scalameta"  % "sbt-mdoc"     % "2.5.0")
+addSbtPlugin("org.scalameta"  % "sbt-mdoc"     % "2.5.1")
 addSbtPlugin("com.github.sbt" % "sbt-git"      % "2.0.1")