Fix the type of handlers options passed to render

When calling #render without arguments, #_render_options infers default
options. Correctly, the type of handlers should be symbols, but now it is
strings.

In Rails7, if the type of handlers isn't symbols, action_view's template
resolver can't find the template. This is because the implementation of template search has been changed to match handlers exactly.

related: https://github.com/rails/rails/pull/42210/files#diff-b356f21d70a4c088415a9c4f315bbccbc979c2ddeda6b8cc5d76770084e5bc6bR31

lib/rspec/rails/example/view_example_group.rb

@@ -150,7 +150,7 @@ def _default_render_options
           match = path_regex.match(_default_file_to_render)
 
           render_options = {template: match[:template]}
-          render_options[:handlers] = [match[:handler]] if match[:handler]
+          render_options[:handlers] = [match[:handler].to_sym] if match[:handler]
           render_options[:formats] = [match[:format].to_sym] if match[:format]
           render_options[:locales] = [match[:locale]] if match[:locale]
           render_options[:variants] = [match[:variant]] if match[:variant]

spec/rspec/rails/example/view_example_group_spec.rb

@@ -151,19 +151,19 @@ def _default_file_to_render; end # Stub method
         it "converts the filename components into render options" do
           allow(view_spec).to receive(:_default_file_to_render) { "widgets/new.en.html.erb" }
           view_spec.render
-          expect(view_spec.received.first).to eq([{template: "widgets/new", locales: ['en'], formats: [:html], handlers: ['erb']}, {}, nil])
+          expect(view_spec.received.first).to eq([{template: "widgets/new", locales: ['en'], formats: [:html], handlers: [:erb]}, {}, nil])
         end
 
         it "converts the filename with variant into render options" do
           allow(view_spec).to receive(:_default_file_to_render) { "widgets/new.en.html+fancy.erb" }
           view_spec.render
-          expect(view_spec.received.first).to eq([{template: "widgets/new", locales: ['en'], formats: [:html], handlers: ['erb'], variants: ['fancy']}, {}, nil])
+          expect(view_spec.received.first).to eq([{template: "widgets/new", locales: ['en'], formats: [:html], handlers: [:erb], variants: ['fancy']}, {}, nil])
         end
 
         it "converts the filename without format into render options" do
           allow(view_spec).to receive(:_default_file_to_render) { "widgets/new.en.erb" }
           view_spec.render
-          expect(view_spec.received.first).to eq([{template: "widgets/new", locales: ['en'], handlers: ['erb']}, {}, nil])
+          expect(view_spec.received.first).to eq([{template: "widgets/new", locales: ['en'], handlers: [:erb]}, {}, nil])
         end
       end