cuirass: Write jobs with ‘pretty-print’.

* build-aux/cuirass/evaluate.scm <top level>: Use ‘pretty-print’ to write the
jobs.

Change-Id: Idf751ddfd133717d390e2295a229e8308d906dc7
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
Merges: #7222

build-aux/cuirass/evaluate.scm

@@ -30,6 +30,7 @@
              (guix ui)
              ((guix ui) #:select (build-notifier))
              (ice-9 match)
+             (ice-9 pretty-print)
              (ice-9 threads))
 
 (define %top-srcdir
@@ -99,7 +100,7 @@
                       (close-inferior inferior)
                       (call-with-output-file file
                         (lambda (port)
-                          (write jobs port)))))))
+                          (pretty-print jobs port)))))))
               %cuirass-supported-systems
               inferiors)))))))
   (x