Marked keystrokes with the :kbd: role.
Fixed the case of the "Ctrl-" prefixes.
diff --git a/Doc/faq/extending.rst b/Doc/faq/extending.rst
index ccd8b28..ade88ae 100644
--- a/Doc/faq/extending.rst
+++ b/Doc/faq/extending.rst
@@ -345,7 +345,7 @@
      {
        line = readline (prompt);
 
-       if (NULL == line)                          /* CTRL-D pressed */
+       if (NULL == line)                          /* Ctrl-D pressed */
        {
          done = 1;
        }