Fix _pkgdown.yml (data set topics removed; link epidatasets topics)

Author: brookslogan

_pkgdown.yml

@@ -103,11 +103,11 @@ reference:
 
   - title: Example data
   - contents:
-      - cases_deaths_subset
-      - archive_cases_dv_subset
-      - covid_incidence_county_subset
-      - covid_incidence_outliers
-      - covid_case_death_rates_extended
+      - epidatasets::cases_deaths_subset
+      - epidatasets::archive_cases_dv_subset
+      - epidatasets::covid_incidence_county_subset
+      - epidatasets::covid_incidence_outliers
+      - epidatasets::covid_case_death_rates_extended
 
   - title: internal
   - contents: