Change double quotes to single quotes

spec/models/wiki_page_spec.rb

@@ -209,17 +209,17 @@ describe WikiPage, models: true do
       end
     end
 
-    context "with same last commit sha" do
-      it "returns true" do
+    context 'with same last commit sha' do
+      it 'returns true' do
         last_commit_sha = @page.commit.sha
-        expect(@page.update("more content", :markdown, nil, last_commit_sha)).to be_truthy
+        expect(@page.update('more content', :markdown, nil, last_commit_sha)).to be_truthy
       end
     end
 
-    context "with different last commit sha" do
-      it "raises exception" do
-        last_commit_sha = "xxx"
-        expect { @page.update("more content", :markdown, nil, last_commit_sha) }.to raise_error(WikiPage::PageChangedError)
+    context 'with different last commit sha' do
+      it 'raises exception' do
+        last_commit_sha = 'xxx'
+        expect { @page.update('more content', :markdown, nil, last_commit_sha) }.to raise_error(WikiPage::PageChangedError)
       end
     end
   end