bpo-32174: Let .chm document display non-ASCII characters properly (GH-9758)


Let .chm document display non-ASCII characters properly

Escape the `body` part of .chm source file to 7-bit ASCII, to fix visual effect on some MBCS Windows systems.
(cherry picked from commit 6261ae9b01fb8429b779169f8de37ff567c144e8)

Co-authored-by: animalize <animalize@users.noreply.github.com>
diff --git a/Doc/conf.py b/Doc/conf.py
index 19a2f7d..b7bb5a0 100644
--- a/Doc/conf.py
+++ b/Doc/conf.py
@@ -14,7 +14,7 @@
 # ---------------------
 
 extensions = ['sphinx.ext.coverage', 'sphinx.ext.doctest',
-              'pyspecific', 'c_annotations']
+              'pyspecific', 'c_annotations', 'escape4chm']
 
 # General substitutions.
 project = 'Python'