makerst: Add missing newline at EOF

(cherry picked from commit d435537f7e63b35c9502b87b7146c846de48b90b)

doc/tools/makerst.py

@@ -1007,7 +1007,7 @@ def make_footer():  # type: () -> str
     return (
         ".. |virtual| replace:: :abbr:`virtual (This method should typically be overridden by the user to have any effect.)`\n"
         ".. |const| replace:: :abbr:`const (This method has no side effects. It doesn't modify any of the instance's member variables.)`\n"
-        ".. |vararg| replace:: :abbr:`vararg (This method accepts any number of arguments after the ones described here.)`"
+        ".. |vararg| replace:: :abbr:`vararg (This method accepts any number of arguments after the ones described here.)`\n"
     )
     # fmt: on