No reason to only have the first three elements from the sphinx version

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

sphinx_rtd_theme/__init__.py

@@ -31,6 +31,12 @@ def config_initiated(app, config):
             _('The canonical_url option is deprecated, use the html_baseurl option from Sphinx instead.')
         )
 
+
+def extend_html_context(app, pagename, templatename, context, doctree):
+     # Add ``sphinx_version_info`` tuple for use in Jinja templates
+     context['sphinx_version_info'] = sphinx_version
+
+
 # See http://www.sphinx-doc.org/en/stable/theming.html#distribute-your-theme-as-a-python-package
 def setup(app):
     if python_version[0] < 3:
@@ -60,4 +66,7 @@ def setup(app):
     else:
         app.config.html_add_permalinks = "\uf0c1"
 
+    # Extend the default context when rendering the templates.
+    app.connect("html-page-context", extend_html_context)
+
     return {'parallel_read_safe': True, 'parallel_write_safe': True}

sphinx_rtd_theme/layout.html

@@ -9,10 +9,6 @@
 {%- set lang_attr = 'en' if language == None else (language | replace('_', '-')) %}
 {%- set sphinx_writer = 'writer-html5' if html5_doctype else 'writer-html4' -%}
 
-{# Build sphinx_version_info tuple from sphinx_version string in pure Jinja #}
-{%- set (_ver_major, _ver_minor, _ver_bugfix) = sphinx_version.split('.') | map('int') -%}
-{%- set sphinx_version_info = (_ver_major, _ver_minor, _ver_bugfix) -%}
-
 <!DOCTYPE html>
 <html class="{{ sphinx_writer }}" lang="{{ lang_attr }}" >
 <head>