Enable strict/explicit code highlighting

docs/conf.py

@@ -54,12 +54,7 @@ master_doc = "index"
 # This pattern also affects html_static_path and html_extra_path.
 exclude_patterns = ["_build", "Thumbs.db", ".DS_Store"]
 
-rst_prolog = """
-.. highlight:: python
-.. currentmodule:: {}
-""".format(
-    project
-)
+rst_prolog = ".. currentmodule:: " + project
 
 # The reST default role (used for this markup: `text`) to use for all
 # documents.
@@ -70,6 +65,10 @@ default_role = "any"
 #
 nitpicky = True
 
+# Prefer strict Python highlighting
+#
+highlight_language = "python3"
+
 # If true, '()' will be appended to :func: etc. cross-reference text.
 #
 add_function_parentheses = False