ClangPlugins: Use underscores instead of dashes in plugin names

This allows arguments to be passed to them from the command line

Meta/Lagom/ClangPlugins/LambdaCapturePluginAction.cpp

@@ -129,4 +129,4 @@ std::unique_ptr<clang::ASTConsumer> LambdaCapturePluginAction::CreateASTConsumer
     return std::make_unique<Consumer>();
 }
 
-static clang::FrontendPluginRegistry::Add<LambdaCapturePluginAction> X("lambda-capture", "analyze lambda captures");
+static clang::FrontendPluginRegistry::Add<LambdaCapturePluginAction> X("lambda_capture", "analyze lambda captures");

Meta/Lagom/ClangPlugins/LibJSGCPluginAction.cpp

@@ -258,4 +258,4 @@ void LibJSGCASTConsumer::HandleTranslationUnit(clang::ASTContext& context)
     visitor.TraverseDecl(context.getTranslationUnitDecl());
 }
 
-static clang::FrontendPluginRegistry::Add<LibJSGCPluginAction> X("libjs-gc-scanner", "analyze LibJS GC usage");
+static clang::FrontendPluginRegistry::Add<LibJSGCPluginAction> X("libjs_gc_scanner", "analyze LibJS GC usage");