Update references to master to point to main in customsourcelink.html (GH-25993)

diff --git a/Doc/tools/templates/customsourcelink.html b/Doc/tools/templates/customsourcelink.html
index fca44e9163cac744c03c4b9a80ffa5c6903f299c..eb9db9e341bd75226a9e5433b6642f89a848b86c 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/master/Doc/{{ sourcename|replace('.rst.txt', '.rst') }}"
+        <a href="https://github.com/python/cpython/blob/main/Doc/{{ sourcename|replace('.rst.txt', '.rst') }}"
             rel="nofollow">{{ _('Show Source') }}
         </a>
       </li>