Fixes #23078 - eliminate trailing whitespace in to_nice_json (#42633)

* Fix #23078 - eliminate trailing whitespace in to_nice_json

* Add changelog fragment for #42633

changelogs/fragments/to-nice-json-separators.yaml

@@ -0,0 +1,2 @@
+minor_changes:
+- to_nice_json - specify separators to json.dumps to normalize the output between python2 and python3 (https://github.com/ansible/ansible/pull/42633)

lib/ansible/plugins/filter/core.py

@@ -87,7 +87,7 @@ def to_json(a, *args, **kw):
 def to_nice_json(a, indent=4, *args, **kw):
     '''Make verbose, human readable JSON'''
     try:
-        return json.dumps(a, indent=indent, sort_keys=True, cls=AnsibleJSONEncoder, *args, **kw)
+        return json.dumps(a, indent=indent, sort_keys=True, separators=(',', ': '), cls=AnsibleJSONEncoder, *args, **kw)
     except Exception as e:
         # Fallback to the to_json filter
         display.warning(u'Unable to convert data using to_nice_json, falling back to to_json: %s' % to_text(e))