[py] add doc for driver_path_env_key (SeleniumHQ#14997)

* Revert "add alias attr to all edge structs"

This reverts commit f17dd08dd32998a310510f0abc44e5b484202a4d.

* Reapply "add alias attr to all edge structs"

This reverts commit cc16e3f.
oops

* [py] add doc for driver_path_env_key

[skip ci]

Author: Delta456

py/selenium/webdriver/chromium/service.py

@@ -32,6 +32,7 @@ class ChromiumService(service.Service):
     :param service_args: (Optional) List of args to be passed to the subprocess when launching the executable.
     :param log_output: (Optional) int representation of STDOUT/DEVNULL, any IO instance or String path to file.
     :param env: (Optional) Mapping of environment variables for the new process, defaults to `os.environ`.
+    :param driver_path_env_key: (Optional) Environment variable to use to get the path to the driver executable.
     """
 
     def __init__(

py/selenium/webdriver/edge/service.py

@@ -32,6 +32,7 @@ class Service(service.ChromiumService):
     :param log_output: (Optional) int representation of STDOUT/DEVNULL, any IO instance or String path to file.
     :param service_args: (Optional) List of args to be passed to the subprocess when launching the executable.
     :param env: (Optional) Mapping of environment variables for the new process, defaults to `os.environ`.
+    :param driver_path_env_key: (Optional) Environment variable to use to get the path to the driver executable.
     """
 
     def __init__(

py/selenium/webdriver/firefox/service.py

@@ -32,6 +32,7 @@ class Service(service.Service):
     :param service_args: (Optional) List of args to be passed to the subprocess when launching the executable.
     :param log_output: (Optional) int representation of STDOUT/DEVNULL, any IO instance or String path to file.
     :param env: (Optional) Mapping of environment variables for the new process, defaults to `os.environ`.
+    :param driver_path_env_key: (Optional) Environment variable to use to get the path to the driver executable.
     """
 
     def __init__(

py/selenium/webdriver/safari/service.py

@@ -32,6 +32,7 @@ class Service(service.Service):
     :param service_args: (Optional) List of args to be passed to the subprocess when launching the executable.
     :param env: (Optional) Mapping of environment variables for the new process, defaults to `os.environ`.
     :param enable_logging: (Optional) Enable logging of the service. Logs can be located at `~/Library/Logs/com.apple.WebDriver/`
+    :param driver_path_env_key: (Optional) Environment variable to use to get the path to the driver executable.
     """
 
     def __init__(