service now passes 'started' instead of 'running'

other modules don't have to implement this directly
also updated docs to prefer 'started'.
fixes #16145

docsite/rst/become.rst

@@ -36,7 +36,7 @@ For example, to manage a system service (which requires ``root`` privileges) whe
     - name: Ensure the httpd service is running
       service:
         name: httpd
-        state: running
+        state: started
       become: true
 
 To run a command as the ``apache`` user::

docsite/rst/playbooks_best_practices.rst

@@ -215,7 +215,7 @@ Below is an example tasks file that explains how a role works.  Our common role
       tags: ntp
 
     - name: be sure ntpd is running and enabled
-      service: name=ntpd state=running enabled=yes
+      service: name=ntpd state=started enabled=yes
       tags: ntp
 
 Here is an example handlers file.  As a review, handlers are only fired when certain tasks report changes, and are run at the end

docsite/rst/playbooks_intro.rst

@@ -126,7 +126,7 @@ the web servers, and then the database servers. For example::
       - name: ensure postgresql is at the latest version
         yum: name=postgresql state=latest
       - name: ensure that postgresql is started
-        service: name=postgresql state=running
+        service: name=postgresql state=started
 
 You can use this method to switch between the host group you're targeting,
 the username logging into the remote servers, whether to sudo or not, and so
@@ -274,7 +274,7 @@ the service module takes ``key=value`` arguments::
 
    tasks:
      - name: make sure apache is running
-       service: name=httpd state=running
+       service: name=httpd state=started
 
 The **command** and **shell** modules are the only modules that just take a list
 of arguments and don't use the ``key=value`` form.  This makes

lib/ansible/plugins/action/service.py

@@ -55,6 +55,10 @@ class ActionModule(ActionBase):
             if 'use' in new_module_args:
                 del new_module_args['use']
 
+            # for backwards compatibility
+            if new_module_args['state'] == 'running':
+                new_module_args['state'] = 'started'
+
             self._display.vvvv("Running %s" % module)
             result.update(self._execute_module(module_name=module, module_args=new_module_args, task_vars=task_vars))
         else: