Rename set_runner -> runner in runner controllers

app/controllers/groups/runners_controller.rb

 class Groups::RunnersController < Groups::ApplicationController
   before_action :authorize_admin_pipeline!
-  before_action :set_runner, only: [:edit, :update, :destroy, :pause, :resume, :show]
+  before_action :runner, only: [:edit, :update, :destroy, :pause, :resume, :show]
   def show
     render 'shared/runners/show'
@@ -41,7 +41,7 @@ def pause
   private
-  def set_runner
+  def runner
     @runner ||= @group.runners.find(params[:id])
   end

app/controllers/projects/runners_controller.rb

 class Projects::RunnersController < Projects::ApplicationController
   before_action :authorize_admin_build!
-  before_action :set_runner, only: [:edit, :update, :destroy, :pause, :resume, :show]
+  before_action :runner, only: [:edit, :update, :destroy, :pause, :resume, :show]
   layout 'project_settings'
@@ -61,7 +61,7 @@ def toggle_group_runners
   protected
-  def set_runner
+  def runner
     @runner ||= project.runners.find(params[:id])
   end