Improve documentation around passing browser args

Author: mdmintz

README.md

@@ -385,8 +385,8 @@ The code above will leave your browser window open in case there's a failure. (i
 --agent=STRING  # (Modify the web browser's User-Agent string.)
 --mobile  # (Use the mobile device emulator while running tests.)
 --metrics=STRING  # (Set mobile metrics: "CSSWidth,CSSHeight,PixelRatio".)
---chromium-arg=ARG  # (Add a Chromium arg for Chrome/Edge, comma-separated.)
---firefox-arg=ARG  # (Add a Firefox arg for Firefox, comma-separated.)
+--chromium-arg="ARG=N,ARG2"  # (Set Chromium args, ","-separated, no spaces.)
+--firefox-arg="ARG=N,ARG2"  # (Set Firefox args, comma-separated, no spaces.)
 --firefox-pref=SET  # (Set a Firefox preference:value set, comma-separated.)
 --extension-zip=ZIP  # (Load a Chrome Extension .zip|.crx, comma-separated.)
 --extension-dir=DIR  # (Load a Chrome Extension directory, comma-separated.)

help_docs/customizing_test_runs.md

@@ -123,8 +123,8 @@ pytest my_first_test.py --settings-file=custom_settings.py
 --agent=STRING  # (Modify the web browser's User-Agent string.)
 --mobile  # (Use the mobile device emulator while running tests.)
 --metrics=STRING  # (Set mobile metrics: "CSSWidth,CSSHeight,PixelRatio".)
---chromium-arg=ARG  # (Add a Chromium arg for Chrome/Edge, comma-separated.)
---firefox-arg=ARG  # (Add a Firefox arg for Firefox, comma-separated.)
+--chromium-arg="ARG=N,ARG2"  # (Set Chromium args, ","-separated, no spaces.)
+--firefox-arg="ARG=N,ARG2"  # (Set Firefox args, comma-separated, no spaces.)
 --firefox-pref=SET  # (Set a Firefox preference:value set, comma-separated.)
 --extension-zip=ZIP  # (Load a Chrome Extension .zip|.crx, comma-separated.)
 --extension-dir=DIR  # (Load a Chrome Extension directory, comma-separated.)

seleniumbase/plugins/pytest_plugin.py

@@ -45,8 +45,8 @@ def pytest_addoption(parser):
     --agent=STRING  (Modify the web browser's User-Agent string.)
     --mobile  (Use the mobile device emulator while running tests.)
     --metrics=STRING  (Set mobile metrics: "CSSWidth,CSSHeight,PixelRatio".)
-    --chromium-arg=ARG  (Add a Chromium arg for Chrome/Edge, comma-separated.)
-    --firefox-arg=ARG  (Add a Firefox arg for Firefox, comma-separated.)
+    --chromium-arg="ARG=N,ARG2" (Set Chromium args, ","-separated, no spaces.)
+    --firefox-arg="ARG=N,ARG2" (Set Firefox args, comma-separated, no spaces.)
     --firefox-pref=SET  (Set a Firefox preference:value set, comma-separated.)
     --extension-zip=ZIP  (Load a Chrome Extension .zip|.crx, comma-separated.)
     --extension-dir=DIR  (Load a Chrome Extension directory, comma-separated.)

seleniumbase/plugins/selenium_plugin.py

@@ -29,8 +29,8 @@ class SeleniumBrowser(Plugin):
     --agent=STRING  (Modify the web browser's User-Agent string.)
     --mobile  (Use the mobile device emulator while running tests.)
     --metrics=STRING  (Set mobile metrics: "CSSWidth,CSSHeight,PixelRatio".)
-    --chromium-arg=ARG  (Add a Chromium arg for Chrome/Edge, comma-separated.)
-    --firefox-arg=ARG  (Add a Firefox arg for Firefox, comma-separated.)
+    --chromium-arg="ARG=N,ARG2" (Set Chromium args, ","-separated, no spaces.)
+    --firefox-arg="ARG=N,ARG2" (Set Firefox args, comma-separated, no spaces.)
     --firefox-pref=SET  (Set a Firefox preference:value set, comma-separated.)
     --extension-zip=ZIP  (Load a Chrome Extension .zip|.crx, comma-separated.)
     --extension-dir=DIR  (Load a Chrome Extension directory, comma-separated.)