roll up of fixes for eos modules (#21406)

* fixes issue with load_provider() not checking for an existing key
* adds updates to eos_config results key
* lots of minor syntax fixes in eos shared module
* adds eos_argument_spec to eos_eapi

fixes #21402

lib/ansible/modules/network/eos/eos_system.py

@@ -143,6 +143,7 @@ import re
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.network_common import ComplexList
 from ansible.module_utils.eos import load_config, get_config
+from ansible.module_utils.eos import eos_argument_spec
 
 _CONFIGURED_VRFS = None
 
@@ -304,6 +305,8 @@ def main():
         state=dict(default='present', choices=['present', 'absent'])
     )
 
+    argument_spec.update(eos_argument_spec)
+
     module = AnsibleModule(argument_spec=argument_spec,
                            supports_check_mode=True)