[1.8.x] Fixed #24695 -- Tidied up a couple of regexes in the CBV docs

Thanks datakid for the report

Backport of b9e972b961 from master

docs/ref/class-based-views/generic-date-based.txt

@@ -593,7 +593,7 @@ DateDetailView
         from django.views.generic.dates import DateDetailView
 
         urlpatterns = [
-            url(r'^(?P<year>[0-9]+)/(?P<month>[-\w]+)/(?P<day>[0-9]+)/(?P<pk>[0-9]+)/$',
+            url(r'^(?P<year>[0-9]{4})/(?P<month>[-\w]+)/(?P<day>[0-9]+)/(?P<pk>[0-9]+)/$',
                 DateDetailView.as_view(model=Article, date_field="pub_date"),
                 name="archive_date_detail"),
         ]

docs/ref/class-based-views/generic-display.txt

@@ -59,7 +59,7 @@ DetailView
         from article.views import ArticleDetailView
 
         urlpatterns = [
-            url(r'^(?P<slug>[-_\w]+)/$', ArticleDetailView.as_view(), name='article-detail'),
+            url(r'^(?P<slug>[-\w]+)/$', ArticleDetailView.as_view(), name='article-detail'),
         ]
 
     **Example myapp/article_detail.html**: