Extract alt style's "go to next" field into a support form helper

I want to reuse this for unlabeled pet styles is why! (That's been the
immediate motivation for this refactor, but also I do just like that
it'll make support forms easier to build.)

app/assets/stylesheets/application/support-form.sass

@@ -89,7 +89,7 @@
 		align-items: center
 		gap: 1em
 
-		label
+	.go-to-next
 		display: flex
 		align-items: center
 		gap: .25em

app/helpers/support_form_helper.rb

@@ -1,7 +1,8 @@
 module SupportFormHelper
 	class SupportFormBuilder < ActionView::Helpers::FormBuilder
 		attr_reader :template
-		delegate :capture, :content_tag, :render, to: :template, private: true
+		delegate :capture, :check_box_tag, :content_tag, :params, :render,
+			to: :template, private: true
 
 		def errors
 			render partial: "application/support_form/errors", locals: {form: self}
@@ -38,6 +39,14 @@ module SupportFormHelper
 		def actions(&block)
 			content_tag(:section, class: "actions", &block)
 		end
+
+		def go_to_next_field(**options, &block)
+			content_tag(:label, class: "go-to-next", **options, &block)
+		end
+
+		def go_to_next_check_box(value)
+			check_box_tag "next", value, checked: params[:next] == value
+		end
 	end
 
 	def support_form_with(**options, &block)

app/views/alt_styles/edit.html.haml

@@ -28,9 +28,8 @@
 
 	= f.actions do
 		= f.submit "Save changes"
-		%label{title: "If checked, takes you to the next unlabeled pet style, if any. Useful for labeling in bulk!"}
-			= check_box_tag "next", "unlabeled-style",
-				checked: params[:next] == "unlabeled-style"
+		= f.go_to_next_field title: "If checked, takes you to the next unlabeled pet style, if any. Useful for labeling in bulk!" do
+			= f.go_to_next_check_box "unlabeled-style"
 			Then: Go to unlabeled style
 
 - content_for :stylesheets do