[Documentation][zos_volume_init] Add and standarize docstrings on modules/zos_volume_init.py (#1392)

* Add and standarize docstrings on module-utils/zos_tso_command.py

* Add changelog fragment

Author: IsaacVRey

changelogs/fragments/1392-update-docstring-zos_volume_init.yml

@@ -0,0 +1,3 @@
+trivial:
+  - zos_volume_init - Updated docstrings to numpy style for visual aid to developers.
+    (https://github.com/ansible-collections/ibm_zos_core/pull/1392).

plugins/modules/zos_volume_init.py

@@ -230,7 +230,13 @@
 
 
 def run_module():
+    """Initialize the module.
 
+    Raises
+    ------
+    fail_json
+        'Index' cannot be False for SMS managed volumes.
+    """
     module_args = dict(
         address=dict(type="str", required=True),
         verify_volid=dict(type="str", required=False),