Move language and library tour to deprecated folder (#6259)

Contributes to #5767

firebase.json

@@ -223,6 +223,7 @@
       { "source": "/guides/language/effective-dart/:page*", "destination": "/effective-dart/:page*", "type": 301 },
       { "source": "/guides/language/extension-methods", "destination": "/language/extension-methods", "type": 301 },
       { "source": "/guides/language/formatting", "destination": "/tools/dart-format", "type": 301 },
+      { "source": "/guides/language/language-tour", "destination": "/deprecated/language-tour", "type": 301 },
       { "source": "/guides/language/library-tour", "destination": "/libraries", "type": 301 },
       { "source": "/guides/language/sound-dart", "destination": "/language/type-system", "type": 301 },
       { "source": "/guides/language/sound-faq", "destination": "/language/type-system", "type": 301 },
@@ -233,6 +234,7 @@
       { "source": "/guides/libraries/create-packages", "destination": "/tools/pub/create-packages", "type": 301 },
       { "source": "/guides/libraries/futures-error-handling", "destination": "/libraries/async/futures-error-handling", "type": 301 },
       { "source": "/guides/libraries/java-interop", "destination": "/interop/java-interop", "type": 301 },
+      { "source": "/guides/libraries/library-tour", "destination": "/deprecated/library-tour", "type": 301 },
       { "source": "/guides/libraries/objective-c-interop", "destination": "/interop/objective-c-interop", "type": 301 },
       { "source": "/guides/libraries/c-interop", "destination": "/interop/c-interop", "type": 301 },
       { "source": "/guides/libraries/private-files", "destination": "/tools/pub/private-files", "type": 301 },

src/content/guides/language/language-tour.md → src/content/deprecated/language-tour.md

@@ -1,12 +1,13 @@
 ---
-title: A tour of the Dart language
-description: A tour of all the major Dart language features.
+title: Deprecated tour of the Dart language
+description: The previous destination of the Dart language tour.
 short-title: Language tour
 js: [{url: '/assets/js/language-tour-redirector.js'}]
 sitemap: false
 canonical: https://dart.dev/language
 noindex: true
 skipFreshness: true
+show_breadcrumbs: false
 ---
 
 :::warning

src/content/guides/libraries/library-tour.md → src/content/deprecated/library-tour.md

@@ -1,12 +1,13 @@
 ---
-title: A tour of the core libraries
-description: Learn about the major features in Dart's libraries.
+title: Deprecated tour of the core libraries
+description: The previous destination of the Dart core library introduction.
 short-title: Library tour
 js: [{url: '/assets/js/library-tour-redirector.js'}]
 sitemap: false
 canonical: https://dart.dev/libraries
 noindex: true
 skipFreshness: true
+show_breadcrumbs: false
 ---
 
 :::warning