Trac #32858: tiny doctest formatting fix in integer_mod_ring.py

The last example for `IntegerModRing_generic.unit_gens()` is not
formatted properly:

https://doc.sagemath.org/html/en/reference/finite_rings/sage/rings/finit
e_rings/integer_mod_ring.html#sage.rings.finite_rings.integer_mod_ring.I
ntegerModRing_generic.unit_gens

Let's add `::` to fix this.

URL: https://trac.sagemath.org/32858
Reported by: lorenz
Ticket author(s): Lorenz Panny
Reviewer(s): Frédéric Chapoton

Author: Release Manager

build/pkgs/configure/checksums.ini

@@ -1,4 +1,4 @@
 tarball=configure-VERSION.tar.gz
-sha1=4625589c083fcf8283f6fc85b59a3faded982e9a
-md5=6898739cd66bd3ef214cf97698a96b3d
-cksum=447189429
+sha1=3658781e6dec76acbbcbc405ebc379a8d66438d0
+md5=a9e8b1ee469619a5fcecfda4e61ffc7e
+cksum=1864932829

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-77671d2e43e382c57209a095092d8562a10bdec5
+5cb64b3cc4129ec37883c15b81f88fb24fe0bc3d

src/sage/rings/finite_rings/integer_mod_ring.py

@@ -1366,7 +1366,7 @@ def unit_gens(self, **kwds):
 
         The choice of generators is affected by the optional keyword
         ``algorithm``; this can be ``'sage'`` (default) or ``'pari'``.
-        See :meth:`unit_group` for details.
+        See :meth:`unit_group` for details. ::
 
             sage: A = Zmod(55)
             sage: A.unit_gens(algorithm='sage')