Replace unprocessable_entity -> unprocessable_content (#35658)

spec/controllers/application_controller_spec.rb

@@ -219,16 +219,16 @@ RSpec.describe ApplicationController do
     it_behaves_like 'error response', 410
   end
 
-  describe 'unprocessable_entity' do
+  describe 'unprocessable_content' do
     controller do
-      def route_unprocessable_entity
-        unprocessable_entity
+      def route_unprocessable_content
+        unprocessable_content
       end
     end
 
     subject do
-      routes.draw { get 'route_unprocessable_entity' => 'anonymous#route_unprocessable_entity' }
-      get 'route_unprocessable_entity'
+      routes.draw { get 'route_unprocessable_content' => 'anonymous#route_unprocessable_content' }
+      get 'route_unprocessable_content'
     end
 
     it_behaves_like 'error response', 422

spec/requests/api/v2/search_spec.rb

@@ -98,7 +98,7 @@ RSpec.describe 'Search API' do
       context 'when search raises syntax error' do
         before { allow(Search).to receive(:new).and_raise(Mastodon::SyntaxError) }
 
-        it 'returns http unprocessable_entity' do
+        it 'returns http unprocessable_content' do
           get '/api/v2/search', headers: headers, params: params
 
           expect(response).to have_http_status(422)