The context property was previously being used in the macro
`git-webhook-url-with-branches` which has been removed as it is not in
use any longer.
The context property was now being used only in 2 integration docs, both
of which used it only in a single location, and directly used their own
names as the channel name. Making the context property unnecessary.
Note: This doesn't change the occurences in the Zapier integration doc,
since they refer to pieces of the UI in Zapier, which may still be using
the "Stream" terminology.
Several integration docs instruct the user to create a bot, but don't
specify that the type of bot should be "Incoming webhook".
Renames create-a-bot.md -> create-an-incoming-webhook.md for clarity,
and replaces all incomplete instructions with this macro.
Renames bot_types.png -> bot_types_incoming_webhook.png and updates
the image with a screenshot of the latest UI.
markdown-include is GPL licensed.
Also, rewrite it as a block processor, so that it works correctly
inside indented blocks.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
