fix(WebExt) missing content after a colon

[PassionPenguin]

content was missing after the colon

-       - : `string`. The URL offered by the OAuth2 service provider to get an access token. The details of this URL should be given in the documentation for the service provider in question, but the URL parameters should always include:
+      - : `string`. The URL offered by the OAuth2 service provider to get an access token. The details of this URL should be given in the documentation for the service provider in question, but the URL parameters should always include: the [redirect URL](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/identity#getting_the_redirect_url) and the extension's [client ID](/en-US/docs/Mozilla/Add-ons/WebExtensions/API/identity#registering_your_add-on).

[github-actions]

Preview URLs

• /en-US/docs/Mozilla/Add-ons/WebExtensions/API/identity/launchWebAuthFlow

[rebloor]

Thanks @PassionPenguin