gh-36771: fix doctest for nauty 2.8.8

Updating to nauty 2.8.8 has one test failing. Fix it in a backwards
compatible way.

Note that nauty output is only debug, and the fact that sagemath tests
this output is dubious (see #35250).

- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.

URL: #36771
Reported by: Gonzalo Tornaría
Reviewer(s): Matthias Köppe

Author: Release Manager

build/pkgs/configure/checksums.ini

@@ -1,4 +1,4 @@
 tarball=configure-VERSION.tar.gz
-sha1=374eca6cdfb4bd3dd2d3173e300639f86407077c
-md5=5810e2d5a26f7457239a576b022b0a19
-cksum=409095104
+sha1=522d5fb44038e051abeed5fc0bd8f26dc0c33dd4
+md5=7c89c8b88491557e0f6d6a351809e886
+cksum=1283778476

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-dcd23be6c05f8de220a8404175c6e4175842255e
+3ae48f93bb78b004a818376fdcf959d661cb838d

src/sage/graphs/graph_generators.py

@@ -1130,7 +1130,7 @@ def nauty_genbg(self, options="", debug=False):
             sage: list(graphs.nauty_genbg("-c1 2", debug=True))
             ['>E Usage: ...genbg [-c -ugs -vq -lzF] [-Z#] [-D#] [-A] [-d#|-d#:#] [-D#|-D#:#] n1 n2...
             sage: list(graphs.nauty_genbg("-c 1 2", debug=True))
-            ['>A ...genbg n=1+2 e=2:2 d=1:1 D=2:1 c\n', Bipartite graph on 3 vertices]
+            ['>A ...genbg n=1+2 e=2:2 d=1:1 D=2:1 c...\n', Bipartite graph on 3 vertices]
 
         We must have n1=1..24, n2=0..32 and n1+n2=1..32 (:trac:`34179`)::