Fix overlap of right-sidebar and wiki create page form

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/39509

app/helpers/nav_helper.rb

@@ -19,11 +19,7 @@ module NavHelper
       end
     elsif current_path?('jobs#show')
       %w[page-gutter build-sidebar right-sidebar-expanded]
-    elsif current_path?('wikis#show') ||
-        current_path?('wikis#edit') ||
-        current_path?('wikis#update') ||
-        current_path?('wikis#history') ||
-        current_path?('wikis#git_access')
+    elsif current_controller?('wikis') && current_action?('show', 'create', 'edit', 'update', 'history', 'git_access')
       %w[page-gutter wiki-sidebar right-sidebar-expanded]
     else
       []

changelogs/unreleased/39509-fix-wiki-create-sidebar-overlap.yml

+---
+title: Fix overlap of right-sidebar and main content when creating a Wiki page
+merge_request:
+author:
+type: fixed