Fix missing interactive spec

* lisp/json.el (json-pretty-print-buffer-ordered): Add interactive
  spec "P" which has been missing.
1 job for master in 60 minutes and 1 second (queued for 4 seconds)
Status Job ID Name Coverage
  Test
failed #868
test-all

01:00:01

 
Name Stage Failure
failed
test-all Test The script exceeded the maximum execution time set for the job
make -C test check-expensive
make[1]: Entering directory '/builds/emacs/emacs/test'
rm -f ./*.tmp
make[2]: Entering directory '/builds/emacs/emacs/test'
make[3]: Entering directory '/builds/emacs/emacs/test'
ELC lisp/net/tramp-tests.elc
GEN lisp/net/tramp-tests.log
Pulling docker image gitlab/gitlab-runner-helper:x86_64-f100a208 ...
ERROR: Job failed: execution took longer than 1h0m0s seconds