Add explicit overrides in ScalaCliScalafixModule

[Gedochao]

Related to com-lihaoyi/mill#5974
It seems mill-moduledefs plugin adding the override keywords at typer intermittently crashes incremental compilation when changing branches in the scala-cli repo.
Making them explicit seems to make the problem go away. 🤷

Checklist

• tested the solution locally and it works

How much have your relied on LLM-based tools in this contribution?

extensively, Claude found the likely cause for me

How was the solution tested?

re-compiling and switching between branches with changes in the Mill build

Additional notes

cc @lihaoyi in case you'd like to minimize this.
Without the changes, the intermittent incremental compilation failures look somewhat like this:

Details

build.mill-68] compile compiling 2 Scala sources to out/mill-build/compile.dest/classes ...
build.mill-68] [error] build.mill:212:10
build.mill-68]   object test extends ScalaCliTests with ScalaCliScalafixModule {
build.mill-68]          ^
build.mill-68] error overriding method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]];
build.mill-68]   method scalacPluginMvnDeps² in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]] module class test$ inherits conflicting members:
build.mill-68]   method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]  and
build.mill-68]   method scalacPluginMvnDeps in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]
build.mill-68] (Note: this can be resolved by declaring an override in module class test$.);
build.mill-68] other members with override errors are:: method scalacOptions
build.mill-68] 
build.mill-68] where:    scalacPluginMvnDeps  is a method in trait ScalaTests
build.mill-68]           scalacPluginMvnDeps² is a method in trait ScalaCliScalafixModule
build.mill-68] 
build.mill-68] 
build.mill-68] [error] build.mill:318:10
build.mill-68]   object test extends ScalaCliTests with ScalaCliScalafixModule {
build.mill-68]          ^
build.mill-68] error overriding method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]];
build.mill-68]   method scalacPluginMvnDeps in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]] module class test$ inherits conflicting members:
build.mill-68]   method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]  and
build.mill-68]   method scalacPluginMvnDeps in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]
build.mill-68] (Note: this can be resolved by declaring an override in module class test$.)
build.mill-68] 
build.mill-68] [error] build.mill:392:7
build.mill-68] trait ProtoBuildModule extends ScalaCliPublishModule with HasTests
build.mill-68]       ^
build.mill-68] error overriding method scalacOptions in trait HasTests of type => mill.api.Task.Simple[Seq[String]];
build.mill-68]   method scalacOptions in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[String]] trait ProtoBuildModule inherits conflicting members:
build.mill-68]   method scalacOptions in trait HasTests of type => mill.api.Task.Simple[Seq[String]]  and
build.mill-68]   method scalacOptions in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[String]]
build.mill-68] (Note: this can be resolved by declaring an override in trait ProtoBuildModule.)
build.mill-68] 
build.mill-68] [error] build.mill:715:10
build.mill-68]   object test extends ScalaCliTests with ScalaCliScalafixModule {
build.mill-68]          ^
build.mill-68] error overriding method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]];
build.mill-68]   method scalacPluginMvnDeps in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]] module class test$ inherits conflicting members:
build.mill-68]   method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]  and
build.mill-68]   method scalacPluginMvnDeps in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]
build.mill-68] (Note: this can be resolved by declaring an override in module class test$.)
build.mill-68] 
build.mill-68] [error] build.mill:764:10
build.mill-68]   object test extends ScalaCliTests with ScalaCliScalafixModule {
build.mill-68]          ^
build.mill-68] error overriding method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]];
build.mill-68]   method scalacPluginMvnDeps in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]] module class test$ inherits conflicting members:
build.mill-68]   method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]  and
build.mill-68]   method scalacPluginMvnDeps in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]
build.mill-68] (Note: this can be resolved by declaring an override in module class test$.)
build.mill-68] 
build.mill-68] [error] build.mill:818:10
build.mill-68]   object test extends ScalaCliTests with ScalaCliScalafixModule
build.mill-68]          ^
build.mill-68] error overriding method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]];
build.mill-68]   method scalacPluginMvnDeps² in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]] module class test$ inherits conflicting members:
build.mill-68]   method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]  and
build.mill-68]   method scalacPluginMvnDeps in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]
build.mill-68] (Note: this can be resolved by declaring an override in module class test$.);
build.mill-68] other members with override errors are:: method scalacOptions
build.mill-68] 
build.mill-68] where:    scalacPluginMvnDeps  is a method in trait ScalaTests
build.mill-68]           scalacPluginMvnDeps² is a method in trait ScalaCliScalafixModule
build.mill-68] 
build.mill-68] 
build.mill-68] [error] build.mill:811:7
build.mill-68] trait DirectivesParserModule extends ScalaCliCrossSbtModule
build.mill-68]       ^
build.mill-68] error overriding method scalacOptions in trait HasTests of type => mill.api.Task.Simple[Seq[String]];
build.mill-68]   method scalacOptions² in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[String]] trait DirectivesParserModule inherits conflicting members:
build.mill-68]   method scalacOptions in trait HasTests of type => mill.api.Task.Simple[Seq[String]]  and
build.mill-68]   method scalacOptions in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[String]]
build.mill-68] (Note: this can be resolved by declaring an override in trait DirectivesParserModule.)
build.mill-68] 
build.mill-68] where:    scalacOptions  is a method in trait HasTests
build.mill-68]           scalacOptions² is a method in trait ScalaCliScalafixModule
build.mill-68] 
build.mill-68] 
build.mill-68] [error] build.mill:999:10
build.mill-68]   object test extends ScalaCliTests with ScalaCliScalafixModule {
build.mill-68]          ^
build.mill-68] error overriding method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]];
build.mill-68]   method scalacPluginMvnDeps² in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]] module class test$ inherits conflicting members:
build.mill-68]   method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]  and
build.mill-68]   method scalacPluginMvnDeps in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]
build.mill-68] (Note: this can be resolved by declaring an override in module class test$.);
build.mill-68] other members with override errors are:: method scalacOptions
build.mill-68] 
build.mill-68] where:    scalacPluginMvnDeps  is a method in trait ScalaTests
build.mill-68]           scalacPluginMvnDeps² is a method in trait ScalaCliScalafixModule
build.mill-68] 
build.mill-68] 
build.mill-68] [error] build.mill:1038:9
build.mill-68]   trait IntegrationScalaTests extends super.ScalaCliTests with ScalaCliScalafixModule {
build.mill-68]         ^
build.mill-68] error overriding method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]];
build.mill-68]   method scalacPluginMvnDeps² in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]] trait IntegrationScalaTests inherits conflicting members:
build.mill-68]   method scalacPluginMvnDeps in trait ScalaTests of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]  and
build.mill-68]   method scalacPluginMvnDeps in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[mill.scalalib.Dep]]
build.mill-68] (Note: this can be resolved by declaring an override in trait IntegrationScalaTests.);
build.mill-68] other members with override errors are:: method scalacOptions
build.mill-68] 
build.mill-68] where:    scalacPluginMvnDeps  is a method in trait ScalaTests
build.mill-68]           scalacPluginMvnDeps² is a method in trait ScalaCliScalafixModule
build.mill-68] 
build.mill-68] 
build.mill-68] [error] build.mill:1361:7
build.mill-68] trait TastyLib extends ScalaCliCrossSbtModule
build.mill-68]       ^
build.mill-68] error overriding method scalacOptions in trait ScalaCliModule of type => mill.api.Task.Simple[Seq[String]];
build.mill-68]   method scalacOptions in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[String]] trait TastyLib inherits conflicting members:
build.mill-68]   method scalacOptions in trait ScalaCliModule of type => mill.api.Task.Simple[Seq[String]]  and
build.mill-68]   method scalacOptions in trait ScalaCliScalafixModule of type => mill.api.Task.Simple[Seq[String]]
build.mill-68] (Note: this can be resolved by declaring an override in trait TastyLib.)
build.mill-68] 
build.mill-68] [error] 10 errors found
68/73+, 1 FAILED] ~/IdeaProjects/scala-cli/millw generate-reference-doc[].run 7s

[lihaoyi]

Seems like the same issue as com-lihaoyi/mill#5211