Fetch all translation keys using a regex

lib/gitlab/i18n/translation_entry.rb

@@ -67,11 +67,7 @@ module Gitlab
       private
 
       def translation_keys
-        @translation_keys ||= if has_plural?
-                                entry_data.keys.select { |key| key =~ /msgstr\[\d+\]/ }
-                              else
-                                [:msgstr]
-                              end
+        @translation_keys ||= entry_data.keys.select { |key| key.to_s =~ /\Amsgstr(\[\d+\])?\z/ }
       end
     end
   end

spec/lib/gitlab/i18n/po_linter_spec.rb

@@ -106,7 +106,7 @@ describe Gitlab::I18n::PoLinter do
     context 'with multiple plurals' do
       let(:po_path) { 'spec/fixtures/multiple_plurals.po' }
 
-      it 'has no errors' do
+      it 'has errors' do
         is_expected.not_to be_empty
       end
     end