docs: update error message (#81554)

* Reword the error message when the module fails to parse parameters
  in JSON format
* misc typo fixes

Fixes: #81188

Signed-off-by: Abhijeet Kasurde <akasurde@redhat.com>

changelogs/fragments/81188_better_error.yml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+  - Reword the error message when the module fails to parse parameters in JSON format (https://github.com/ansible/ansible/issues/81188).

lib/ansible/module_utils/basic.py

@@ -379,8 +379,8 @@ def _load_params():
     try:
         params = json.loads(buffer.decode('utf-8'))
     except ValueError:
-        # This helper used too early for fail_json to work.
+        # This helper is used too early for fail_json to work.
-        print('\n{"msg": "Error: Module unable to decode valid JSON on stdin.  Unable to figure out what parameters were passed", "failed": true}')
+        print('\n{"msg": "Error: Module unable to decode stdin/parameters as valid JSON. Unable to parse what parameters were passed", "failed": true}')
         sys.exit(1)
 
     if PY2:
@@ -391,7 +391,7 @@ def _load_params():
     except KeyError:
         # This helper does not have access to fail_json so we have to print
         # json output on our own.
-        print('\n{"msg": "Error: Module unable to locate ANSIBLE_MODULE_ARGS in json data from stdin.  Unable to figure out what parameters were passed", '
+        print('\n{"msg": "Error: Module unable to locate ANSIBLE_MODULE_ARGS in JSON data from stdin. Unable to figure out what parameters were passed", '
               '"failed": true}')
         sys.exit(1)
 
@@ -560,7 +560,7 @@ class AnsibleModule(object):
             raise AssertionError("implementation error -- version and date must not both be set")
         deprecate(msg, version=version, date=date, collection_name=collection_name)
         # For compatibility, we accept that neither version nor date is set,
-        # and treat that the same as if version would haven been set
+        # and treat that the same as if version would not have been set
         if date is not None:
             self.log('[DEPRECATION WARNING] %s %s' % (msg, date))
         else:
@@ -687,7 +687,7 @@ class AnsibleModule(object):
 
     def find_mount_point(self, path):
         '''
-            Takes a path and returns it's mount point
+            Takes a path and returns its mount point
 
         :param path: a string type with a filesystem path
         :returns: the path to the mount point as a text type