patch 8.2.4997: Python: changing hidden buffer can cause display mess up

Problem:    Python: changing hidden buffer can cause the display to be messed
            up.
Solution:   Do not mark changed lines when using another buffer. (Paul Ollis,
            closes #10437, closes #7972)
diff --git a/src/if_py_both.h b/src/if_py_both.h
index 0d0a5ce..240cc96 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -4676,9 +4676,11 @@
 	// Only adjust marks if we managed to switch to a window that holds
 	// the buffer, otherwise line numbers will be invalid.
 	if (save_curbuf.br_buf == NULL)
+	{
 	    mark_adjust((linenr_T)lo, (linenr_T)(hi - 1),
 						  (long)MAXLNUM, (long)extra);
-	changed_lines((linenr_T)lo, 0, (linenr_T)hi, (long)extra);
+	    changed_lines((linenr_T)lo, 0, (linenr_T)hi, (long)extra);
+	}
 
 	if (buf == curbuf && (switchwin.sw_curwin != NULL
 					   || save_curbuf.br_buf == NULL))