feat: add git-derived lastmod to sitemap and fix canonical URLs

.github/workflows/build-sphinx-docs.yml

@@ -26,6 +26,9 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          filter: blob:none
       - name: Setup Python
         uses: actions/setup-python@v5
         with:

docs/conf.py

@@ -125,10 +125,10 @@ def setup(app):
 html_show_sourcelink = True  # False on private repos; True on public repos
 html_theme = 'pydata_sphinx_theme'
 html_title = project
-html_baseurl = 'https://docs.saltproject.io/salt/user-guide/'
-
-# Extends baseurl, in combination with version value
-sitemap_locales = ['en']
+html_baseurl = 'https://docs.saltproject.io/salt/user-guide/en/latest/'
+sitemap_url_scheme = "{link}"   # lang/version now live in html_baseurl, so canonical is correct too
+sitemap_locales = [None]        # single-language site: drop redundant self-referential xhtml:link alternates
+sitemap_show_lastmod = True     # git commit time of each source .rst
 # Pages we don't care to include in generated sitemap file
 sitemap_excludes = [
     "search.html",

docs/requirements.txt

@@ -4,6 +4,6 @@ sphinx-copybutton>=0.5.1
 sphinx-design>=0.3.0
 sphinx-inline-tabs>=2022.1.2b11
 sphinx-prompt
-sphinx-sitemap==2.6.0
+sphinx-sitemap==2.9.0
 sphinx-tabs>=3.4.1
 sphinx>=5.3.0