[3.13] Link to plaintext for "show source" links (GH-137131) (#137133)

Co-authored-by: ryan-duve <ryan-duve@users.noreply.github.com>

diff --git a/Doc/tools/templates/customsourcelink.html b/Doc/tools/templates/customsourcelink.html
index 43d3a7a892a880e60bc82eac4c9fc81805251578..8e271bca1e08c8545e2b07aefa61ac565fa3158e 100644 (file)
--- a/Doc/tools/templates/customsourcelink.html
+++ b/Doc/tools/templates/customsourcelink.html
@@ -4,7 +4,7 @@
     <ul class="this-page-menu">
       <li><a href="{{ pathto('bugs') }}">{% trans %}Report a bug{% endtrans %}</a></li>
       <li>
-        <a href="https://github.com/python/cpython/blob/main/Doc/{{ sourcename|replace('.rst.txt', '.rst') }}"
+        <a href="https://github.com/python/cpython/blob/main/Doc/{{ sourcename|replace('.rst.txt', '.rst') }}?plain=1"
             rel="nofollow">{{ _('Show source') }}
         </a>
       </li>