Applying modified version of patch #1018386, which fixes
some escaping bugs in SRE.
diff --git a/Doc/lib/libre.tex b/Doc/lib/libre.tex
index 7d59ee5..704db30 100644
--- a/Doc/lib/libre.tex
+++ b/Doc/lib/libre.tex
@@ -387,7 +387,8 @@
Octal escapes are included in a limited form: If the first digit is a
0, or if there are three octal digits, it is considered an octal
-escape. Otherwise, it is a group reference.
+escape. Otherwise, it is a group reference. As for string literals,
+octal escapes are always at most three digits in length.
% Note the lack of a period in the section title; it causes problems