[doc] refactor: unify NuxtJS and Nuxt.js to Nuxt

[vuejs-jp-bot]

本家のドキュメントに更新がありました 📄
Original: nuxt@39ab720
updatedFiles:
content/en/_collections/events/2019.md
content/en/_collections/events/2020.md
content/en/announcements/0.nuxt-static-improvements.md
content/en/announcements/3.nuxtjs-from-terminal-to-browser.md
content/en/announcements/4.introducing-smart-prefetching.md
content/en/announcements/index.md
content/en/contribution-guide/index.md
content/en/design/index.md
content/en/docs/1.get-started/1.installation.md
content/en/docs/1.get-started/2.routing.md
content/en/docs/1.get-started/3.directory-structure.md
content/en/docs/1.get-started/4.commands.md
content/en/docs/1.get-started/5.conclusion.md
content/en/docs/1.get-started/6.upgrading.md
content/en/docs/2.concepts/1.views.md
content/en/docs/2.concepts/2.context-helpers.md
content/en/docs/2.concepts/3.server-side-rendering.md
content/en/docs/2.concepts/5.nuxt-lifecycle.md
content/en/docs/3.features/10.transitions.md
content/en/docs/3.features/11.live-preview.md
content/en/docs/3.features/2.deployment-targets.md
content/en/docs/3.features/3.file-system-routing.md
content/en/docs/3.features/4.data-fetching.md
content/en/docs/3.features/5.meta-tags-seo.md
content/en/docs/3.features/6.configuration.md
content/en/docs/3.features/7.loading.md
content/en/docs/3.features/8.nuxt-components.md
content/en/docs/3.features/9.component-discovery.md
content/en/docs/4.directory-structure/1.nuxt.md
content/en/docs/4.directory-structure/10.plugins.md
content/en/docs/4.directory-structure/11.static.md
content/en/docs/4.directory-structure/12.store.md
content/en/docs/4.directory-structure/13.nuxt-config.md
content/en/docs/4.directory-structure/2.assets.md
content/en/docs/4.directory-structure/4.content.md
content/en/docs/4.directory-structure/5.dist.md
content/en/docs/4.directory-structure/8.modules.md
content/en/docs/4.directory-structure/9.pages.md
content/en/docs/5.configuration-glossary/1.configuration-alias.md
content/en/docs/5.configuration-glossary/10.configuration-extend-plugins.md
content/en/docs/5.configuration-glossary/11.configuration-generate.md
content/en/docs/5.configuration-glossary/12.configuration-global-name.md
content/en/docs/5.configuration-glossary/13.configuration-head.md
content/en/docs/5.configuration-glossary/15.configuration-ignore.md
content/en/docs/5.configuration-glossary/16.configuration-loading.md
content/en/docs/5.configuration-glossary/2.configuration-build.md
content/en/docs/5.configuration-glossary/20.configuration-modules.md
content/en/docs/5.configuration-glossary/21.configuration-modulesdir.md
content/en/docs/5.configuration-glossary/22.configuration-plugins.md
content/en/docs/5.configuration-glossary/23.configuration-render.md
content/en/docs/5.configuration-glossary/24.configuration-rootdir.md
content/en/docs/5.configuration-glossary/25.configuration-router.md
content/en/docs/5.configuration-glossary/27.configuration-server.md
content/en/docs/5.configuration-glossary/28.configuration-servermiddleware.md
content/en/docs/5.configuration-glossary/29.configuration-srcdir.md
content/en/docs/5.configuration-glossary/3.configuration-builddir.md
content/en/docs/5.configuration-glossary/32.configuration-telemetry.md
content/en/docs/5.configuration-glossary/4.configuration-cli.md
content/en/docs/5.configuration-glossary/5.configuration-css.md
content/en/docs/5.configuration-glossary/6.configuration-components.md
content/en/docs/5.configuration-glossary/7.configuration-dev.md
content/en/docs/5.configuration-glossary/8.configuration-dir.md
content/en/docs/5.configuration-glossary/9.configuration-env.md
content/en/docs/6.internals-glossary/10.nuxt-render.md
content/en/docs/6.internals-glossary/12.nuxt-render-and-get-window.md
content/en/docs/6.internals-glossary/2.$nuxt.md
content/en/docs/6.internals-glossary/3.internals.md
content/en/docs/6.internals-glossary/9.nuxt.md
content/en/docs/7.components-glossary/1.fetch.md
content/en/docs/7.components-glossary/2.head.md
content/en/docs/7.components-glossary/5.loading.md
content/en/docs/7.components-glossary/7.transition.md
content/en/docs/7.components-glossary/8.scrolltotop.md
content/en/docs/7.components-glossary/9.validate.md
content/en/index.md
content/en/integrations/deployments/0.vercel.md
content/en/integrations/deployments/1.netlify.md
content/en/integrations/deployments/2.layer0.md
content/en/integrations/deployments/21yunbox.md
content/en/integrations/deployments/azure-portal.md
content/en/integrations/deployments/azure-static-web-apps.md
content/en/integrations/deployments/digital-ocean.md
content/en/integrations/deployments/dokku.md
content/en/integrations/deployments/fume.md
content/en/integrations/deployments/github-pages.md
content/en/integrations/deployments/google-appengine.md
content/en/integrations/deployments/heroku.md
content/en/integrations/deployments/hostman.md
content/en/integrations/deployments/platformsh.md
content/en/integrations/deployments/pm2.md
content/en/integrations/deployments/qovery.md
content/en/integrations/deployments/surge.md
content/en/releases/index.md
content/en/showcases/index.md
content/en/sponsors/index.md
content/en/tutorials/1.creating-blog-with-nuxt-content.md
content/en/tutorials/2.improve-your-developer-experience-with-nuxt-components.md
content/en/tutorials/3.going-dark-with-nuxtjs-color-mode.md
content/en/tutorials/4.moving-from-nuxtjs-dotenv-to-runtime-config.md
content/en/tutorials/5.build-dev-to-clone-with-nuxt-new-fetch.md
content/en/tutorials/index.md
content/en/video-courses/index.md