s3_bucket - Improve documentation of the policy parameter (#387)

s3_bucket - improve documentation of policy parameter

SUMMARY
This pull requests improves the documentation of the policy parameter in the s3_bucket module. It documents how to ensure the absence of a policy.
Fixes #385
ISSUE TYPE

Docs Pull Request

COMPONENT NAME
s3_bucket

Reviewed-by: Jill R <None>
Reviewed-by: Moritz Wagner <None>
Reviewed-by: None <None>
Reviewed-by: Mark Chappell <None>

plugins/modules/s3_bucket.py

@@ -41,7 +41,7 @@
     type: str
   policy:
     description:
-      - The JSON policy as a string.
+      - The JSON policy as a string. Set to the string C("null") to force the absence of a policy.
     type: json
   s3_url:
     description:
@@ -214,7 +214,7 @@
     public_access:
         block_public_acls: true
         ignore_public_acls: true
-        ## keys == 'false' can be ommited, undefined keys defaults to 'false'
+        ## keys == 'false' can be omitted, undefined keys defaults to 'false'
         # block_public_policy: false
         # restrict_public_buckets: false
 
@@ -235,6 +235,12 @@
     name: mys3bucket
     state: present
     delete_object_ownership: true
+
+# Delete a bucket policy from bucket
+- amazon.aws.s3_bucket:
+    name: mys3bucket
+    state: present
+    policy: "null"
 '''
 
 import json