Update sysrand documentation (#17676)

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

doc/lib.rst

@@ -272,18 +272,18 @@ Math libraries
 * `random <random.html>`_
   Fast and tiny random number generator.
 
-* `sysrand <sysrand.html>`_
-  Cryptographically secure pseudorandom number generator.
-
 * `rationals <rationals.html>`_
   This module implements rational numbers and relevant mathematical operations.
 
 * `stats <stats.html>`_
-  Statistical analysis
+  Statistical analysis.
 
 * `sums <sums.html>`_
   Accurate summation functions.
 
+* `sysrand <sysrand.html>`_
+  Cryptographically secure pseudorandom number generator.
+
 
 Internet Protocols and Support
 ------------------------------