chore: remove language from sitemap paths (#2373)

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Fixes #<issue_number_goes_here> 🦕

Author: tswast

docs/conf.py

@@ -267,6 +267,12 @@
 
 # https://sphinx-sitemap.readthedocs.io/en/latest/getting-started.html#usage
 html_baseurl = "https://dataframes.bigquery.dev/"
+sitemap_locales = [None]
+
+# We don't have any immediate plans to translate the API reference, so omit the
+# language from the URLs.
+# https://sphinx-sitemap.readthedocs.io/en/latest/advanced-configuration.html#configuration-customizing-url-scheme
+sitemap_url_scheme = "{link}"
 
 # -- Options for warnings ------------------------------------------------------