PyDoc: changes to the generated conf.py file

- Set the highlight language to python3 (excludes python2 syntax).
- Set the encoding for code highlighting to utf-8 (no need to detect).
- Update deprecated variable name.
- Remove redundant unicode prefixed string.

doc/python_api/sphinx_doc_gen.py

@@ -1814,11 +1814,16 @@ def write_sphinx_conf_py(basepath):
     fw("extensions = ['sphinx.ext.intersphinx']\n\n")
     fw("intersphinx_mapping = {'blender_manual': ('https://docs.blender.org/manual/en/dev/', None)}\n\n")
     fw("project = 'Blender %s Python API'\n" % BLENDER_VERSION_STRING)
-    fw("master_doc = 'index'\n")
-    fw("copyright = u'Blender Foundation'\n")
+    fw("root_doc = 'index'\n")
+    fw("copyright = 'Blender Foundation'\n")
     fw("version = '%s'\n" % BLENDER_VERSION_DOTS)
     fw("release = '%s'\n" % BLENDER_VERSION_DOTS)
 
+    # Set this as the default is a super-set of Python3.
+    fw("highlight_language = 'python3'\n")
+    # No need to detect encoding.
+    fw("highlight_options = {'default': {'encoding': 'utf-8'}}\n\n")
+
     # Quiet file not in table-of-contents warnings.
     fw("exclude_patterns = [\n")
     fw("    'include__bmesh.rst',\n")