docs: update docstring (#986)

Author: KazuCocoa

appium/webdriver/webdriver.py

@@ -118,7 +118,7 @@ def test_command(self, argument):
                 def add_command(self):
                     return ('post', 'session/$sessionId/path/to/your/custom/url')
 
-            driver = webdriver.Remote('http://localhost:4723/wd/hub', desired_caps,
+            driver = webdriver.Remote('http://localhost:4723/wd/hub', options=options,
                 extensions=[YourCustomCommand])
 
             # Then, the driver sends a post request to `session/$sessionId/path/to/your/custom/url`
@@ -138,7 +138,7 @@ def custom_method_name(self, element_id):
                 def add_command(self):
                     return ('GET', 'session/$sessionId/path/to/your/custom/$id/url')
 
-            driver = webdriver.Remote('http://localhost:4723/wd/hub', desired_caps,
+            driver = webdriver.Remote('http://localhost:4723/wd/hub', options=options,
                 extensions=[YourCustomCommand])
             element = driver.find_elemeent(by=AppiumBy.ACCESSIBILITY_ID, value='id')