Restore `replace-region-contents' in json-pretty-print

* lisp/json.el (json-pretty-print): Switch back to using
`replace-region-contents' to preserve markers and fonts which went
missing when fixing the bug
(bug#34160).
(json-pretty-print-max-secs): Restore, too.
1 job for master in 77 minutes and 37 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
failed #2817
test-all

01:17:37

 
Name Stage Failure
failed
test-all Test
Makefile:318: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
Makefile:293: recipe for target 'check-expensive' failed
make[1]: *** [check-expensive] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
Makefile:959: recipe for target 'check-expensive' failed
make: *** [check-expensive] Error 2
ERROR: Job failed: exit code 1