Add explanation of resume_charging-limitations (#282)

The stop/resume commands have some limitations that aren't very intuitive if you haven't struggled directly with the API (and maybe not even then). Added some clarification to the readme to hopefully reduce questions/confusion and avoid issues like #278.

Also correct some misnamed deprecated services.

Author: steinmn

README.md

@@ -170,23 +170,48 @@ Starting and stopping charging can be done by several methods. If the charger
 is configured to not require authentication, connecting the charger to the
 EV will by default start charging.
 
-To start the charging from HA, this can be done in several ways:
-
-- Press the _"Resume charging"_ button, or
-- Toggle the _"Charging"_ switch, or
-- Send `zaptec.restart_charger` service call (deprecated)
-
-Similarly, pausing the charging can be done by:
+To stop the charging from HA, this can be done in several ways:
 
 - Pressing the _"Stop charging"_ button, or
 - Turn off the _"Charging"_ switch, or
-- Send `zaptec.stop_pause_charging` service call (deprecated)
+- Send `zaptec.stop_charging` service call (deprecated)
+
+Similarly, starting the charging again can be done by:
+
+- Press the _"Resume charging"_ button, or
+- Turn on the _"Charging"_ switch, or
+- Send `zaptec.resume_charging` service call (deprecated)
 
 > [!TIP]
 > Zaptec will unlock the cable when charging is paused unless it is permanently
 > locked.
 
 
+### The limitations of the Resume command
+
+It is important to understand that the _"Resume charging"_ command as it is
+implemented in the Zaptec API will only start charging if the charger was
+stopped by a _"Stop charging"_ command.
+
+Some example cases where the _"Resume charging"_ command will **not** start
+charging:
+
+* Charging current is set to `0 A` (
+  [Setting charging current](#setting-charging-current)).
+* The car has reached its configured target battery level.
+* The charging was stopped using the app/api of the car.
+* The charging has stopped because the time is outside of the charging schedule
+  configured in the app of the car.
+
+> [!TIP]
+> As a general rule: To start charging, you need to reverse what stopped it in
+> the first place.
+
+> [!NOTE]
+> The charging buttons will only be available/clickable when the command they
+> trigger is valid.
+
+
 ## Prevent charging auto start
 
 Zaptec will by default start charging as soon as everything is ready
@@ -215,7 +240,7 @@ the same time.
 > [!NOTE]
 > This entity is adjusting the available current for the entire installation.
 > If the installation has several chargers installed, changing this value will
-> affect all.
+> affect all of them.
 
 > [!IMPORTANT]
 > Many EVs don't like getting too frequent changes to the available charge